diff mbox

[PR64164] drop copyrename, integrate into expand

Message ID orwpxqvqnp.fsf@livre.home
State New
Headers show

Commit Message

Alexandre Oliva July 23, 2015, 3:29 p.m. UTC
On Jul 23, 2015, Richard Biener <richard.guenther@gmail.com> wrote:

> Hmm, ok.  Does using

>    if (currently_expanding_to_rtl)

> work?  I think it's slightly more descriptive.

Yeah.  Thanks, I've tested it with this change, and I'm now checking
this in (full patch first; adjusted incremental patch at the end):

[PR64164] Drop copyrename, use coalescible partition as base when optimizing.

From: Alexandre Oliva <aoliva@redhat.com>

for  gcc/ChangeLog

	PR rtl-optimization/64164
	* Makefile.in (OBJS): Drop tree-ssa-copyrename.o.
	* tree-ssa-copyrename.c: Removed.
	* opts.c (default_options_table): Drop -ftree-copyrename.  Add
	-ftree-coalesce-vars.
	* passes.def: Drop all occurrences of pass_rename_ssa_copies.
	* common.opt (ftree-copyrename): Ignore.
	(ftree-coalesce-inlined-vars): Likewise.
	* doc/invoke.texi: Remove the ignored options above.
	* gimple-expr.h (gimple_can_coalesce_p): Move declaration
	* tree-ssa-coalesce.h: ... here.
	* tree-ssa-uncprop.c: Include tree-ssa-coalesce.h and other
	headers required by it.
	* gimple-expr.c (gimple_can_coalesce_p): Allow coalescing
	across variables when flag_tree_coalesce_vars.  Check register
	use and promoted modes to allow coalescing.  Moved to
	tree-ssa-coalesce.c.
	* tree-ssa-live.c (struct tree_int_map_hasher): Move along
	with its member functions to tree-ssa-coalesce.c.
	(var_map_base_init): Likewise.  Renamed to
	compute_samebase_partition_bases.
	(partition_view_normal): Drop want_bases parameter.
	(partition_view_bitmap): Likewise.
	* tree-ssa-live.h: Adjust declarations.
	* tree-ssa-coalesce.c: Include explow.h.
	(build_ssa_conflict_graph): Process PARM_ and RESULT_DECLs's
	default defs at the entry point.
	(dump_part_var_map): New.
	(compute_optimized_partition_bases): New, called by...
	(coalesce_ssa_name): ... when flag_tree_coalesce_vars, instead
	of compute_samebase_partition_bases.  Adjust.
	* alias.c (nonoverlapping_memrefs_p): Disregard gimple-regs.
	* cfgexpand.c (leader_merge): New.
	(get_rtl_for_parm_ssa_default_def): New.
	(set_rtl): Merge exprs and attrs, even for MEMs and non-SSA
	vars.  Update DECL_RTL for PARM_DECLs and RESULT_DECLs too.
	(expand_one_stack_var_at): Handle anonymous SSA_NAMEs.  Drop
	redundant MEM attr setting.
	(expand_one_stack_var_1): Handle anonymous SSA_NAMEs.  Renamed
	from...
	(expand_one_stack_var): ... this.  New wrapper to check and
	skip already expanded SSA partitions.
	(record_alignment_for_reg_var): New, factored out of...
	(expand_one_var): ... this.
	(expand_one_ssa_partition): New.
	(adjust_one_expanded_partition_var): New.
	(expand_one_register_var): Check and skip already expanded SSA
	partitions.
	(expand_used_vars): Don't create DECLs for anonymous SSA
	names.  Expand all SSA partitions, then adjust all SSA names.
	(pass::execute): Replace the loops that set
	SA.partition_to_pseudo from partition leaders and cleared
	DECL_RTL for multi-location variables, and that which used to
	rename vars and set attrs, with one that clears DECL_RTL and
	checks that PARMs and RESULTs default_defs match DECL_RTL.
	* cfgexpand.h (get_rtl_for_parm_ssa_default_def): Declare.
	* emit-rtl.c (set_reg_attrs_for_parm): Handle NULL decl.
	* explow.c (promote_ssa_mode): New.
	* explow.h (promote_ssa_mode): Declare.
	* expr.c (expand_expr_real_1): Handle anonymous SSA_NAMEs.
	* function.c: Include cfgexpand.h.
	(use_register_for_decl): Handle SSA_NAMEs, anonymous or not.
	(use_register_for_parm_decl): Wrapper for the above to
	special-case the result_ptr.
	(rtl_for_parm): Ditto for get_rtl_for_parm_ssa_default_def.
	(split_complex_args): Take assign_parm_data_all argument.
	Pass it to rtl_for_parm.  Set up rtl and context for split
	args.
	(assign_parms_augmented_arg_list): Adjust.
	(maybe_reset_rtl_for_parm): Reset DECL_RTL of parms with
	multiple locations.  Recognize split complex args.
	(assign_parm_adjust_stack_rtl): Add all and parm arguments,
	for rtl_for_parm.  For SSA-assigned parms, zero stack_parm.
	(assign_parm_setup_block): Prefer SSA-assigned location.
	(assign_parm_setup_reg): Likewise.  Use entry_parm for equiv
	if stack_parm is NULL.
	(assign_parm_setup_stack): Prefer SSA-assigned location.
	(assign_parms): Maybe reset DECL_RTL of params.  Adjust stack
	rtl before testing for pointer bounds.  Special-case result_ptr.
	(expand_function_start): Maybe reset DECL_RTL of result.
	Prefer SSA-assigned location for result and static chain.
	Factor out DECL_RESULT and SET_DECL_RTL.
	* tree-outof-ssa.c (insert_value_copy_on_edge): Handle
	anonymous SSA names.  Use promote_ssa_mode.
	(get_temp_reg): Likewise.
	(remove_ssa_form): Adjust.
	* stor-layout.c (layout_decl): Don't set mem attributes of
	non-MEMs.
	* var-tracking.c (dataflow_set_clear_at_call): Take call_insn
	and get its reg_usage for reg invalidation.
	(compute_bb_dataflow): Pass it insn.
	(emit_notes_in_bb): Likewise.

for  gcc/testsuite/ChangeLog

	PR rtl-optimization/64164
	* gcc.dg/guality/pr54200.c: Add -fno-tree-coalesce-vars.
	* gcc.dg/ssp-1.c: Make counter a register.
	* gcc.dg/ssp-2.c: Likewise.
	* gcc.dg/torture/parm-coalesce.c: New.
---
 gcc/Makefile.in                              |    1 
 gcc/alias.c                                  |   13 +
 gcc/cfgexpand.c                              |  370 +++++++++++++++-----
 gcc/cfgexpand.h                              |    2 
 gcc/common.opt                               |   12 -
 gcc/doc/invoke.texi                          |   48 +--
 gcc/emit-rtl.c                               |    5 
 gcc/explow.c                                 |   29 ++
 gcc/explow.h                                 |    3 
 gcc/expr.c                                   |   39 +-
 gcc/function.c                               |  275 ++++++++++++---
 gcc/gimple-expr.c                            |   39 --
 gcc/gimple-expr.h                            |    1 
 gcc/opts.c                                   |    2 
 gcc/passes.def                               |    5 
 gcc/stor-layout.c                            |    3 
 gcc/testsuite/gcc.dg/guality/pr54200.c       |    2 
 gcc/testsuite/gcc.dg/ssp-1.c                 |    2 
 gcc/testsuite/gcc.dg/ssp-2.c                 |    2 
 gcc/testsuite/gcc.dg/torture/parm-coalesce.c |   40 ++
 gcc/tree-outof-ssa.c                         |   16 -
 gcc/tree-ssa-coalesce.c                      |  378 ++++++++++++++++++++-
 gcc/tree-ssa-coalesce.h                      |    1 
 gcc/tree-ssa-copyrename.c                    |  475 --------------------------
 gcc/tree-ssa-live.c                          |   99 -----
 gcc/tree-ssa-live.h                          |    4 
 gcc/tree-ssa-uncprop.c                       |    5 
 gcc/var-tracking.c                           |   12 -
 28 files changed, 1030 insertions(+), 853 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/torture/parm-coalesce.c
 delete mode 100644 gcc/tree-ssa-copyrename.c

Comments

Segher Boessenkool July 23, 2015, 8:31 p.m. UTC | #1
On Thu, Jul 23, 2015 at 12:29:14PM -0300, Alexandre Oliva wrote:
> Yeah.  Thanks, I've tested it with this change, and I'm now checking
> this in (full patch first; adjusted incremental patch at the end):

Unfortunately it causes about a thousand test fails on powerpc64-linux
(at least, it seems to be this patch, I haven't actually checked).

Some representative backtraces:


/home/segher/src/gcc/gcc/testsuite/gcc.c-torture/compile/pr54713-1.c: In function 'f1':
/home/segher/src/gcc/gcc/testsuite/gcc.c-torture/compile/pr54713-1.c:13:1: internal compiler error: in expand_one_stack_var_1, at cfgexpand.c:1221
0x1030eae7 expand_one_stack_var_1
	/home/segher/src/gcc/gcc/cfgexpand.c:1221
0x10320a23 expand_one_ssa_partition
	/home/segher/src/gcc/gcc/cfgexpand.c:1295
0x10320a23 expand_used_vars
	/home/segher/src/gcc/gcc/cfgexpand.c:1940
0x10322ea3 execute
	/home/segher/src/gcc/gcc/cfgexpand.c:6084


/home/segher/src/gcc/gcc/testsuite/gcc.c-torture/compile/pr39928-1.c: In function 'vq_nbest':
/home/segher/src/gcc/gcc/testsuite/gcc.c-torture/compile/pr39928-1.c:6:1: internal compiler error: in emit_move_insn, at expr.c:3552
0x1046f587 emit_move_insn(rtx_def*, rtx_def*)
	/home/segher/src/gcc/gcc/expr.c:3551
0x104daa67 assign_parm_setup_reg
	/home/segher/src/gcc/gcc/function.c:3322
0x104dd063 assign_parms
	/home/segher/src/gcc/gcc/function.c:3766
0x104e0aa7 expand_function_start(tree_node*)
	/home/segher/src/gcc/gcc/function.c:5192
0x10322f07 execute
	/home/segher/src/gcc/gcc/cfgexpand.c:6105


I have the full testsuite logs if you want them.


Segher
H.J. Lu July 23, 2015, 8:57 p.m. UTC | #2
On Thu, Jul 23, 2015 at 1:31 PM, Segher Boessenkool
<segher@kernel.crashing.org> wrote:
> On Thu, Jul 23, 2015 at 12:29:14PM -0300, Alexandre Oliva wrote:
>> Yeah.  Thanks, I've tested it with this change, and I'm now checking
>> this in (full patch first; adjusted incremental patch at the end):
>
> Unfortunately it causes about a thousand test fails on powerpc64-linux
> (at least, it seems to be this patch, I haven't actually checked).
>

It also caused:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66978
H.J. Lu July 23, 2015, 9:59 p.m. UTC | #3
On Thu, Jul 23, 2015 at 1:57 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Jul 23, 2015 at 1:31 PM, Segher Boessenkool
> <segher@kernel.crashing.org> wrote:
>> On Thu, Jul 23, 2015 at 12:29:14PM -0300, Alexandre Oliva wrote:
>>> Yeah.  Thanks, I've tested it with this change, and I'm now checking
>>> this in (full patch first; adjusted incremental patch at the end):
>>
>> Unfortunately it causes about a thousand test fails on powerpc64-linux
>> (at least, it seems to be this patch, I haven't actually checked).
>>
>
> It also caused:
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66978
>

and maybe:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983
David Edelsohn July 23, 2015, 11:14 p.m. UTC | #4
On Thu, Jul 23, 2015 at 5:59 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Jul 23, 2015 at 1:57 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Thu, Jul 23, 2015 at 1:31 PM, Segher Boessenkool
>> <segher@kernel.crashing.org> wrote:
>>> On Thu, Jul 23, 2015 at 12:29:14PM -0300, Alexandre Oliva wrote:
>>>> Yeah.  Thanks, I've tested it with this change, and I'm now checking
>>>> this in (full patch first; adjusted incremental patch at the end):
>>>
>>> Unfortunately it causes about a thousand test fails on powerpc64-linux
>>> (at least, it seems to be this patch, I haven't actually checked).
>>>
>>
>> It also caused:
>>
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66978
>>
>
> and maybe:
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983

I request that this patch be reverted (again).

Thanks, David
H.J. Lu July 23, 2015, 11:19 p.m. UTC | #5
On Thu, Jul 23, 2015 at 4:14 PM, David Edelsohn <dje.gcc@gmail.com> wrote:
> On Thu, Jul 23, 2015 at 5:59 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Thu, Jul 23, 2015 at 1:57 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Thu, Jul 23, 2015 at 1:31 PM, Segher Boessenkool
>>> <segher@kernel.crashing.org> wrote:
>>>> On Thu, Jul 23, 2015 at 12:29:14PM -0300, Alexandre Oliva wrote:
>>>>> Yeah.  Thanks, I've tested it with this change, and I'm now checking
>>>>> this in (full patch first; adjusted incremental patch at the end):
>>>>
>>>> Unfortunately it causes about a thousand test fails on powerpc64-linux
>>>> (at least, it seems to be this patch, I haven't actually checked).
>>>>
>>>
>>> It also caused:
>>>
>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66978
>>>
>>
>> and maybe:
>>
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983
>
> I request that this patch be reverted (again).

And I request to test any new patches under x32 before checking in.
You can use Ubuntu 14 to test x32.

Thanks.
Richard Biener July 24, 2015, 9:22 a.m. UTC | #6
On Fri, Jul 24, 2015 at 1:19 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Jul 23, 2015 at 4:14 PM, David Edelsohn <dje.gcc@gmail.com> wrote:
>> On Thu, Jul 23, 2015 at 5:59 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>> On Thu, Jul 23, 2015 at 1:57 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>> On Thu, Jul 23, 2015 at 1:31 PM, Segher Boessenkool
>>>> <segher@kernel.crashing.org> wrote:
>>>>> On Thu, Jul 23, 2015 at 12:29:14PM -0300, Alexandre Oliva wrote:
>>>>>> Yeah.  Thanks, I've tested it with this change, and I'm now checking
>>>>>> this in (full patch first; adjusted incremental patch at the end):
>>>>>
>>>>> Unfortunately it causes about a thousand test fails on powerpc64-linux
>>>>> (at least, it seems to be this patch, I haven't actually checked).
>>>>>
>>>>
>>>> It also caused:
>>>>
>>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66978
>>>>
>>>
>>> and maybe:
>>>
>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983
>>
>> I request that this patch be reverted (again).
>
> And I request to test any new patches under x32 before checking in.
> You can use Ubuntu 14 to test x32.

x32 is neither primary nor secondary arch.

Richard.

> Thanks.
>
> --
> H.J.
Alexandre Oliva July 24, 2015, 6:01 p.m. UTC | #7
On Jul 23, 2015, Segher Boessenkool <segher@kernel.crashing.org> wrote:

> On Thu, Jul 23, 2015 at 12:29:14PM -0300, Alexandre Oliva wrote:
>> Yeah.  Thanks, I've tested it with this change, and I'm now checking
>> this in (full patch first; adjusted incremental patch at the end):

> Unfortunately it causes about a thousand test fails on powerpc64-linux
> (at least, it seems to be this patch, I haven't actually checked).

Yeah, the backtrace suggests very strongly that it's my patch.
Apologies for the breakage.  I'm looking into it right now.

> I have the full testsuite logs if you want them.

Preprocessed testcases would probably help more than the logs, but at
least one of the testcases you mentioned doesn't require any libraries,
so I'm going to start with them.  Then, I'll find some ppc64-linux-gnu
box in the build farm and run some bootstrap and regression testing
there.
Alexandre Oliva July 24, 2015, 6:43 p.m. UTC | #8
On Jul 23, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983

My test logs with the patch have:

PASS: c-c++-common/dfp/func-vararg-dfp.c execution test

so I think this one is not caused by the PR64164 patch.
H.J. Lu July 24, 2015, 7:10 p.m. UTC | #9
On Fri, Jul 24, 2015 at 11:43 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
> On Jul 23, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983
>
> My test logs with the patch have:
>
> PASS: c-c++-common/dfp/func-vararg-dfp.c execution test
>
> so I think this one is not caused by the PR64164 patch.

I double checked.  r226113 failed and r226112 passed.
David Edelsohn July 24, 2015, 7:12 p.m. UTC | #10
On Fri, Jul 24, 2015 at 3:10 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Fri, Jul 24, 2015 at 11:43 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
>> On Jul 23, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>>
>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983
>>
>> My test logs with the patch have:
>>
>> PASS: c-c++-common/dfp/func-vararg-dfp.c execution test
>>
>> so I think this one is not caused by the PR64164 patch.
>
> I double checked.  r226113 failed and r226112 passed.

Alexandre,

Did you commit the final, complete version of the patches?

Did you test the version of the patches that you committed?

Thanks, David
Alexandre Oliva July 24, 2015, 8:02 p.m. UTC | #11
On Jul 23, 2015, David Edelsohn <dje.gcc@gmail.com> wrote:

> I request that this patch be reverted (again).

Might I kindly ask you to please do so for me.  I've just found out
that, after yesterday's memory upgrade on my local build machine, the
filesystem that I normally use for GCC development got corrupted, and I
don't want to mess with it before running an fsck which will take me a
while.

Apologies for the breakage.  I'll add ppc64-linux-gnu regression testing
to the test list for this patchset.  Thanks,
Alexandre Oliva July 24, 2015, 8:33 p.m. UTC | #12
On Jul 24, 2015, David Edelsohn <dje.gcc@gmail.com> wrote:

> Did you commit the final, complete version of the patches?

Yes, I have double-checked that reverting the patch I posted on the
r225979 tree I used for testing reverts it to the base revision, except
for unrelated libgfortran configury changes that I used to avoid halting
configure in cross builds, to increase the amount of code build during
the cross testing.

> Did you test the version of the patches that you committed?

Yes, I have just double-checked that the version I tested is identical
to the change introduced by commit 226113, except for the ChangeLogs and
the libgfortran configury change.

It could be that some other change between 225979 and 226112, combined
with 226113, caused the regression.  Or it could be that my
i686-pc-linux-gnu "native" testing on x86_64-pc-linux-gnu is somehow
faulty.  I'll look into it and try to find out what the source of the
difference in test results H.J. and I get could be.
Alexandre Oliva July 24, 2015, 8:36 p.m. UTC | #13
On Jul 24, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:

> On Fri, Jul 24, 2015 at 11:43 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
>> On Jul 23, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>> 
>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983
>> 
>> My test logs with the patch have:
>> 
>> PASS: c-c++-common/dfp/func-vararg-dfp.c execution test
>> 
>> so I think this one is not caused by the PR64164 patch.

> I double checked.  r226113 failed and r226112 passed.

Weird.  Here's the asm I got, after re-running the command used to
compiled this test with -save-temps.  I checked that the produced
executable is an ELF32 executable, and that it completes execution
successfully.

How does it compare to yours?
H.J. Lu July 24, 2015, 8:47 p.m. UTC | #14
On Fri, Jul 24, 2015 at 1:36 PM, Alexandre Oliva <aoliva@redhat.com> wrote:
> On Jul 24, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>
>> On Fri, Jul 24, 2015 at 11:43 AM, Alexandre Oliva <aoliva@redhat.com> wrote:
>>> On Jul 23, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>>>
>>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983
>>>
>>> My test logs with the patch have:
>>>
>>> PASS: c-c++-common/dfp/func-vararg-dfp.c execution test
>>>
>>> so I think this one is not caused by the PR64164 patch.
>
>> I double checked.  r226113 failed and r226112 passed.
>
> Weird.  Here's the asm I got, after re-running the command used to
> compiled this test with -save-temps.  I checked that the produced
> executable is an ELF32 executable, and that it completes execution
> successfully.
>
> How does it compare to yours?

Please add -msse2:

[hjl@gnu-ivb-1 gcc]$
/export/gnu/import/git/gcc-regression/master/226113/bld/gcc/xgcc
-B/export/gnu/import/git/gcc-regression/master/226113/bld/gcc/
/export/gnu/import/git/gcc-regression/gcc/gcc/testsuite/c-c++-common/dfp/func-vararg-dfp.c
-m32 -fno-diagnostics-show-caret -fdiagnostics-color=never -std=gnu99
-march=i686  -msse2
[hjl@gnu-ivb-1 gcc]$ ./a.out
Segmentation fault (core dumped)
[hjl@gnu-ivb-1 gcc]$
/export/gnu/import/git/gcc-regression/master/226113/bld/gcc/xgcc
-B/export/gnu/import/git/gcc-regression/master/226113/bld/gcc/
/export/gnu/import/git/gcc-regression/gcc/gcc/testsuite/c-c++-common/dfp/func-vararg-dfp.c
-m32 -fno-diagnostics-show-caret -fdiagnostics-color=never -std=gnu99
-march=i686
[hjl@gnu-ivb-1 gcc]$ ./a.out
[hjl@gnu-ivb-1 gcc]$
David Edelsohn July 25, 2015, 1:29 a.m. UTC | #15
On Fri, Jul 24, 2015 at 4:02 PM, Alexandre Oliva <aoliva@redhat.com> wrote:
> On Jul 23, 2015, David Edelsohn <dje.gcc@gmail.com> wrote:
>
>> I request that this patch be reverted (again).
>
> Might I kindly ask you to please do so for me.  I've just found out
> that, after yesterday's memory upgrade on my local build machine, the
> filesystem that I normally use for GCC development got corrupted, and I
> don't want to mess with it before running an fsck which will take me a
> while.

I have reverted the patch.

- David
Richard Biener July 25, 2015, 6:22 a.m. UTC | #16
On July 24, 2015 10:47:37 PM GMT+02:00, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>On Fri, Jul 24, 2015 at 1:36 PM, Alexandre Oliva <aoliva@redhat.com>
>wrote:
>> On Jul 24, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>>
>>> On Fri, Jul 24, 2015 at 11:43 AM, Alexandre Oliva
><aoliva@redhat.com> wrote:
>>>> On Jul 23, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>>>>
>>>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983
>>>>
>>>> My test logs with the patch have:
>>>>
>>>> PASS: c-c++-common/dfp/func-vararg-dfp.c execution test
>>>>
>>>> so I think this one is not caused by the PR64164 patch.
>>
>>> I double checked.  r226113 failed and r226112 passed.
>>
>> Weird.  Here's the asm I got, after re-running the command used to
>> compiled this test with -save-temps.  I checked that the produced
>> executable is an ELF32 executable, and that it completes execution
>> successfully.
>>
>> How does it compare to yours?
>
>Please add -msse2:

Yes, the fails appear with -m32 multilib testing on x86_64.

Richard.

>[hjl@gnu-ivb-1 gcc]$
>/export/gnu/import/git/gcc-regression/master/226113/bld/gcc/xgcc
>-B/export/gnu/import/git/gcc-regression/master/226113/bld/gcc/
>/export/gnu/import/git/gcc-regression/gcc/gcc/testsuite/c-c++-common/dfp/func-vararg-dfp.c
>-m32 -fno-diagnostics-show-caret -fdiagnostics-color=never -std=gnu99
>-march=i686  -msse2
>[hjl@gnu-ivb-1 gcc]$ ./a.out
>Segmentation fault (core dumped)
>[hjl@gnu-ivb-1 gcc]$
>/export/gnu/import/git/gcc-regression/master/226113/bld/gcc/xgcc
>-B/export/gnu/import/git/gcc-regression/master/226113/bld/gcc/
>/export/gnu/import/git/gcc-regression/gcc/gcc/testsuite/c-c++-common/dfp/func-vararg-dfp.c
>-m32 -fno-diagnostics-show-caret -fdiagnostics-color=never -std=gnu99
>-march=i686
>[hjl@gnu-ivb-1 gcc]$ ./a.out
>[hjl@gnu-ivb-1 gcc]$
Alexandre Oliva July 27, 2015, 9:22 p.m. UTC | #17
On Jul 24, 2015, David Edelsohn <dje.gcc@gmail.com> wrote:

> On Fri, Jul 24, 2015 at 4:02 PM, Alexandre Oliva <aoliva@redhat.com> wrote:
>> On Jul 23, 2015, David Edelsohn <dje.gcc@gmail.com> wrote:
>> 
>>> I request that this patch be reverted (again).
>> 
>> Might I kindly ask you to please do so for me.  I've just found out
>> that, after yesterday's memory upgrade on my local build machine, the
>> filesystem that I normally use for GCC development got corrupted, and I
>> don't want to mess with it before running an fsck which will take me a
>> while.

> I have reverted the patch.

Thank you very much.  Long story short, the filesystem got corrupted
beyond repair before I realized something was wrong, so I spend my
weekend backing up the bits I still could and recreating it all from
scratch.  *fun* :-/

I even ran memtest before booting up, but everything was fine in the
single-threaded tests it runs by default.  It was only with all cores
actively using memory intensely that something overheated (memory
modules?  chipset?  cpu?  no clue) and started randomly corrupting bits.
So, I'm now back at lower memory clock speeds, and everything appears to
be rock solid again.  Phew!  So, I'm back to debugging the
newly-reported problems and thinking how much further I should extend
testing coverage so that the next round doesn't have to be reverted
again ;-)

Thanks again,
H.J. Lu July 27, 2015, 9:41 p.m. UTC | #18
On Mon, Jul 27, 2015 at 2:22 PM, Alexandre Oliva <aoliva@redhat.com> wrote:
> On Jul 24, 2015, David Edelsohn <dje.gcc@gmail.com> wrote:
>
>> On Fri, Jul 24, 2015 at 4:02 PM, Alexandre Oliva <aoliva@redhat.com> wrote:
>>> On Jul 23, 2015, David Edelsohn <dje.gcc@gmail.com> wrote:
>>>
>>>> I request that this patch be reverted (again).
>>>
>>> Might I kindly ask you to please do so for me.  I've just found out
>>> that, after yesterday's memory upgrade on my local build machine, the
>>> filesystem that I normally use for GCC development got corrupted, and I
>>> don't want to mess with it before running an fsck which will take me a
>>> while.
>
>> I have reverted the patch.
>
> Thank you very much.  Long story short, the filesystem got corrupted
> beyond repair before I realized something was wrong, so I spend my
> weekend backing up the bits I still could and recreating it all from
> scratch.  *fun* :-/
>
> I even ran memtest before booting up, but everything was fine in the
> single-threaded tests it runs by default.  It was only with all cores
> actively using memory intensely that something overheated (memory
> modules?  chipset?  cpu?  no clue) and started randomly corrupting bits.
> So, I'm now back at lower memory clock speeds, and everything appears to
> be rock solid again.  Phew!  So, I'm back to debugging the

The exactly same thing happened to my machine.  It took me
several weeks before I lowered memory clock.  My machine has
been running fine for over a year under very heavy load.

BTW, this is what I use to test ia32 on Intel64:

PATH=/usr/local32/bin:/bin:/usr/bin
.../configure --prefix=/usr/6.0.0 --enable-clocale=gnu
--with-system-zlib --enable-shared --with-demangler-in-ld
--enable-libmpx i686-linux --with-fpmath=sse
--enable-languages=c,c++,fortran,java,lto,objc

where /usr/local32/bin has ia32 binutils.
Alexandre Oliva July 29, 2015, 8:10 p.m. UTC | #19
On Jul 23, 2015, Segher Boessenkool <segher@kernel.crashing.org> wrote:

> On Thu, Jul 23, 2015 at 12:29:14PM -0300, Alexandre Oliva wrote:
>> Yeah.  Thanks, I've tested it with this change, and I'm now checking
>> this in (full patch first; adjusted incremental patch at the end):

> Unfortunately it causes about a thousand test fails on powerpc64-linux
> (at least, it seems to be this patch, I haven't actually checked).

> Some representative backtraces:

Thanks, both of these are now fixed (at least in that they don't ICE any
more) in the git branch aoliva/pr64164, but I'm going to investigate a
few more issues before I start a regression test on gcc110 and gcc112.
Alexandre Oliva July 29, 2015, 8:13 p.m. UTC | #20
On Jul 23, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:

>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66978

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983

Thanks, both of these are also fixed (I merged your patch for x32, and I
verified manually that another fix I just wrote fixes all the -m32
-msse2 regressions) in the git branch aoliva/pr64164, but I'm going to
investigate a few more issues affecting other targets before I start
full regression tests all over the build farm ;-)
H.J. Lu July 29, 2015, 8:23 p.m. UTC | #21
On Wed, Jul 29, 2015 at 1:13 PM, Alexandre Oliva <aoliva@redhat.com> wrote:
> On Jul 23, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>
>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66978
>
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983
>
> Thanks, both of these are also fixed (I merged your patch for x32, and I
> verified manually that another fix I just wrote fixes all the -m32
> -msse2 regressions) in the git branch aoliva/pr64164, but I'm going to
> investigate a few more issues affecting other targets before I start
> full regression tests all over the build farm ;-)
>

I am building x32 on aoliva/pr64164 now.
H.J. Lu July 30, 2015, 4:42 p.m. UTC | #22
On Wed, Jul 29, 2015 at 1:23 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Wed, Jul 29, 2015 at 1:13 PM, Alexandre Oliva <aoliva@redhat.com> wrote:
>> On Jul 23, 2015, "H.J. Lu" <hjl.tools@gmail.com> wrote:
>>
>>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66978
>>
>>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66983
>>
>> Thanks, both of these are also fixed (I merged your patch for x32, and I
>> verified manually that another fix I just wrote fixes all the -m32
>> -msse2 regressions) in the git branch aoliva/pr64164, but I'm going to
>> investigate a few more issues affecting other targets before I start
>> full regression tests all over the build farm ;-)
>>
>
> I am building x32 on aoliva/pr64164 now.

aoliva/pr64164  is fine on x32.

Thanks.
diff mbox

Patch

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 333461b..16d5582 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1444,7 +1444,6 @@  OBJS = \
 	tree-ssa-ccp.o \
 	tree-ssa-coalesce.o \
 	tree-ssa-copy.o \
-	tree-ssa-copyrename.o \
 	tree-ssa-dce.o \
 	tree-ssa-dom.o \
 	tree-ssa-dse.o \
diff --git a/gcc/alias.c b/gcc/alias.c
index 3203722..69e3732 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -2507,6 +2507,19 @@  nonoverlapping_memrefs_p (const_rtx x, const_rtx y, bool loop_invariant)
   if (! DECL_P (exprx) || ! DECL_P (expry))
     return 0;
 
+  /* If we refer to different gimple registers, or one gimple register
+     and one non-gimple-register, we know they can't overlap.  First,
+     gimple registers don't have their addresses taken.  Now, there
+     could be more than one stack slot for (different versions of) the
+     same gimple register, but we can presumably tell they don't
+     overlap based on offsets from stack base addresses elsewhere.
+     It's important that we don't proceed to DECL_RTL, because gimple
+     registers may not pass DECL_RTL_SET_P, and make_decl_rtl won't be
+     able to do anything about them since no SSA information will have
+     remained to guide it.  */
+  if (is_gimple_reg (exprx) || is_gimple_reg (expry))
+    return exprx != expry;
+
   /* With invalid code we can end up storing into the constant pool.
      Bail out to avoid ICEing when creating RTL for this.
      See gfortran.dg/lto/20091028-2_0.f90.  */
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index a047632..0b19953 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -150,21 +150,121 @@  gimple_assign_rhs_to_tree (gimple stmt)
 
 #define SSAVAR(x) (TREE_CODE (x) == SSA_NAME ? SSA_NAME_VAR (x) : x)
 
+/* Choose either CUR or NEXT as the leader DECL for a partition.
+   Prefer ignored decls, to simplify debug dumps and reduce ambiguity
+   out of the same user variable being in multiple partitions (this is
+   less likely for compiler-introduced temps).  */
+
+static tree
+leader_merge (tree cur, tree next)
+{
+  if (cur == NULL || cur == next)
+    return next;
+
+  if (DECL_P (cur) && DECL_IGNORED_P (cur))
+    return cur;
+
+  if (DECL_P (next) && DECL_IGNORED_P (next))
+    return next;
+
+  return cur;
+}
+
+
+/* Return the RTL for the default SSA def of a PARM or RESULT, if
+   there is one.  */
+
+rtx
+get_rtl_for_parm_ssa_default_def (tree var)
+{
+  gcc_assert (TREE_CODE (var) == PARM_DECL || TREE_CODE (var) == RESULT_DECL);
+
+  if (!is_gimple_reg (var))
+    return NULL_RTX;
+
+  /* If we've already determined RTL for the decl, use it.  This is
+     not just an optimization: if VAR is a PARM whose incoming value
+     is unused, we won't find a default def to use its partition, but
+     we still want to use the location of the parm, if it was used at
+     all.  During assign_parms, until a location is assigned for the
+     VAR, RTL can only for a parm or result if we're not coalescing
+     across variables, when we know we're coalescing all SSA_NAMEs of
+     each parm or result, and we're not coalescing them with names
+     pertaining to other variables, such as other parms' default
+     defs.  */
+  if (DECL_RTL_SET_P (var))
+    {
+      gcc_assert (DECL_RTL (var) != pc_rtx);
+      return DECL_RTL (var);
+    }
+
+  tree name = ssa_default_def (cfun, var);
+
+  if (!name)
+    return NULL_RTX;
+
+  int part = var_to_partition (SA.map, name);
+  if (part == NO_PARTITION)
+    return NULL_RTX;
+
+  return SA.partition_to_pseudo[part];
+}
+
 /* Associate declaration T with storage space X.  If T is no
    SSA name this is exactly SET_DECL_RTL, otherwise make the
    partition of T associated with X.  */
 static inline void
 set_rtl (tree t, rtx x)
 {
+  if (x && SSAVAR (t))
+    {
+      bool skip = false;
+      tree cur = NULL_TREE;
+
+      if (MEM_P (x))
+	cur = MEM_EXPR (x);
+      else if (REG_P (x))
+	cur = REG_EXPR (x);
+      else if (GET_CODE (x) == CONCAT
+	       && REG_P (XEXP (x, 0)))
+	cur = REG_EXPR (XEXP (x, 0));
+      else if (GET_CODE (x) == PARALLEL)
+	cur = REG_EXPR (XVECEXP (x, 0, 0));
+      else if (x == pc_rtx)
+	skip = true;
+      else
+	gcc_unreachable ();
+
+      tree next = skip ? cur : leader_merge (cur, SSAVAR (t));
+
+      if (cur != next)
+	{
+	  if (MEM_P (x))
+	    set_mem_attributes (x, next, true);
+	  else
+	    set_reg_attrs_for_decl_rtl (next, x);
+	}
+    }
+
   if (TREE_CODE (t) == SSA_NAME)
     {
-      SA.partition_to_pseudo[var_to_partition (SA.map, t)] = x;
-      if (x && !MEM_P (x))
-	set_reg_attrs_for_decl_rtl (SSA_NAME_VAR (t), x);
-      /* For the benefit of debug information at -O0 (where vartracking
-         doesn't run) record the place also in the base DECL if it's
-	 a normal variable (not a parameter).  */
-      if (x && x != pc_rtx && TREE_CODE (SSA_NAME_VAR (t)) == VAR_DECL)
+      int part = var_to_partition (SA.map, t);
+      if (part != NO_PARTITION)
+	{
+	  if (SA.partition_to_pseudo[part])
+	    gcc_assert (SA.partition_to_pseudo[part] == x);
+	  else
+	    SA.partition_to_pseudo[part] = x;
+	}
+      /* For the benefit of debug information at -O0 (where
+         vartracking doesn't run) record the place also in the base
+         DECL.  For PARMs and RESULTs, we may end up resetting these
+         in function.c:maybe_reset_rtl_for_parm, but in some rare
+         cases we may need them (unused and overwritten incoming
+         value, that at -O0 must share the location with the other
+         uses in spite of the missing default def), and this may be
+         the only chance to preserve them.  */
+      if (x && x != pc_rtx && SSA_NAME_VAR (t))
 	{
 	  tree var = SSA_NAME_VAR (t);
 	  /* If we don't yet have something recorded, just record it now.  */
@@ -862,7 +962,9 @@  expand_one_stack_var_at (tree decl, rtx base, unsigned base_align,
   gcc_assert (offset == trunc_int_for_mode (offset, Pmode));
 
   x = plus_constant (Pmode, base, offset);
-  x = gen_rtx_MEM (DECL_MODE (SSAVAR (decl)), x);
+  x = gen_rtx_MEM (TREE_CODE (decl) == SSA_NAME
+		   ? TYPE_MODE (TREE_TYPE (decl))
+		   : DECL_MODE (SSAVAR (decl)), x);
 
   if (TREE_CODE (decl) != SSA_NAME)
     {
@@ -884,7 +986,6 @@  expand_one_stack_var_at (tree decl, rtx base, unsigned base_align,
       DECL_USER_ALIGN (decl) = 0;
     }
 
-  set_mem_attributes (x, SSAVAR (decl), true);
   set_rtl (decl, x);
 }
 
@@ -1099,13 +1200,22 @@  account_stack_vars (void)
    to a variable to be allocated in the stack frame.  */
 
 static void
-expand_one_stack_var (tree var)
+expand_one_stack_var_1 (tree var)
 {
   HOST_WIDE_INT size, offset;
   unsigned byte_align;
 
-  size = tree_to_uhwi (DECL_SIZE_UNIT (SSAVAR (var)));
-  byte_align = align_local_variable (SSAVAR (var));
+  if (TREE_CODE (var) == SSA_NAME)
+    {
+      tree type = TREE_TYPE (var);
+      size = tree_to_uhwi (TYPE_SIZE_UNIT (type));
+      byte_align = TYPE_ALIGN_UNIT (type);
+    }
+  else
+    {
+      size = tree_to_uhwi (DECL_SIZE_UNIT (var));
+      byte_align = align_local_variable (var);
+    }
 
   /* We handle highly aligned variables in expand_stack_vars.  */
   gcc_assert (byte_align * BITS_PER_UNIT <= MAX_SUPPORTED_STACK_ALIGNMENT);
@@ -1116,6 +1226,27 @@  expand_one_stack_var (tree var)
 			   crtl->max_used_stack_slot_alignment, offset);
 }
 
+/* Wrapper for expand_one_stack_var_1 that checks SSA_NAMEs are
+   already assigned some MEM.  */
+
+static void
+expand_one_stack_var (tree var)
+{
+  if (TREE_CODE (var) == SSA_NAME)
+    {
+      int part = var_to_partition (SA.map, var);
+      if (part != NO_PARTITION)
+	{
+	  rtx x = SA.partition_to_pseudo[part];
+	  gcc_assert (x);
+	  gcc_assert (MEM_P (x));
+	  return;
+	}
+    }
+
+  return expand_one_stack_var_1 (var);
+}
+
 /* A subroutine of expand_one_var.  Called to assign rtl to a VAR_DECL
    that will reside in a hard register.  */
 
@@ -1125,13 +1256,114 @@  expand_one_hard_reg_var (tree var)
   rest_of_decl_compilation (var, 0, 0);
 }
 
+/* Record the alignment requirements of some variable assigned to a
+   pseudo.  */
+
+static void
+record_alignment_for_reg_var (unsigned int align)
+{
+  if (SUPPORTS_STACK_ALIGNMENT
+      && crtl->stack_alignment_estimated < align)
+    {
+      /* stack_alignment_estimated shouldn't change after stack
+         realign decision made */
+      gcc_assert (!crtl->stack_realign_processed);
+      crtl->stack_alignment_estimated = align;
+    }
+
+  /* stack_alignment_needed > PREFERRED_STACK_BOUNDARY is permitted.
+     So here we only make sure stack_alignment_needed >= align.  */
+  if (crtl->stack_alignment_needed < align)
+    crtl->stack_alignment_needed = align;
+  if (crtl->max_used_stack_slot_alignment < align)
+    crtl->max_used_stack_slot_alignment = align;
+}
+
+/* Create RTL for an SSA partition.  */
+
+static void
+expand_one_ssa_partition (tree var)
+{
+  int part = var_to_partition (SA.map, var);
+  gcc_assert (part != NO_PARTITION);
+
+  if (SA.partition_to_pseudo[part])
+    return;
+
+  if (!use_register_for_decl (var))
+    {
+      expand_one_stack_var_1 (var);
+      return;
+    }
+
+  unsigned int align = MINIMUM_ALIGNMENT (TREE_TYPE (var),
+					  TYPE_MODE (TREE_TYPE (var)),
+					  TYPE_ALIGN (TREE_TYPE (var)));
+
+  /* If the variable alignment is very large we'll dynamicaly allocate
+     it, which means that in-frame portion is just a pointer.  */
+  if (align > MAX_SUPPORTED_STACK_ALIGNMENT)
+    align = POINTER_SIZE;
+
+  record_alignment_for_reg_var (align);
+
+  machine_mode reg_mode = promote_ssa_mode (var, NULL);
+
+  rtx x = gen_reg_rtx (reg_mode);
+
+  set_rtl (var, x);
+}
+
+/* Record the association between the RTL generated for a partition
+   and the underlying variable of the SSA_NAME.  */
+
+static void
+adjust_one_expanded_partition_var (tree var)
+{
+  if (!var)
+    return;
+
+  tree decl = SSA_NAME_VAR (var);
+
+  int part = var_to_partition (SA.map, var);
+  if (part == NO_PARTITION)
+    return;
+
+  rtx x = SA.partition_to_pseudo[part];
+
+  set_rtl (var, x);
+
+  if (!REG_P (x))
+    return;
+
+  /* Note if the object is a user variable.  */
+  if (decl && !DECL_ARTIFICIAL (decl))
+    mark_user_reg (x);
+
+  if (POINTER_TYPE_P (decl ? TREE_TYPE (decl) : TREE_TYPE (var)))
+    mark_reg_pointer (x, get_pointer_alignment (var));
+}
+
 /* A subroutine of expand_one_var.  Called to assign rtl to a VAR_DECL
    that will reside in a pseudo register.  */
 
 static void
 expand_one_register_var (tree var)
 {
-  tree decl = SSAVAR (var);
+  if (TREE_CODE (var) == SSA_NAME)
+    {
+      int part = var_to_partition (SA.map, var);
+      if (part != NO_PARTITION)
+	{
+	  rtx x = SA.partition_to_pseudo[part];
+	  gcc_assert (x);
+	  gcc_assert (REG_P (x));
+	  return;
+	}
+      gcc_unreachable ();
+    }
+
+  tree decl = var;
   tree type = TREE_TYPE (decl);
   machine_mode reg_mode = promote_decl_mode (decl, NULL);
   rtx x = gen_reg_rtx (reg_mode);
@@ -1265,21 +1497,7 @@  expand_one_var (tree var, bool toplevel, bool really_expand)
 	align = POINTER_SIZE;
     }
 
-  if (SUPPORTS_STACK_ALIGNMENT
-      && crtl->stack_alignment_estimated < align)
-    {
-      /* stack_alignment_estimated shouldn't change after stack
-         realign decision made */
-      gcc_assert (!crtl->stack_realign_processed);
-      crtl->stack_alignment_estimated = align;
-    }
-
-  /* stack_alignment_needed > PREFERRED_STACK_BOUNDARY is permitted.
-     So here we only make sure stack_alignment_needed >= align.  */
-  if (crtl->stack_alignment_needed < align)
-    crtl->stack_alignment_needed = align;
-  if (crtl->max_used_stack_slot_alignment < align)
-    crtl->max_used_stack_slot_alignment = align;
+  record_alignment_for_reg_var (align);
 
   if (TREE_CODE (origvar) == SSA_NAME)
     {
@@ -1713,48 +1931,18 @@  expand_used_vars (void)
   if (targetm.use_pseudo_pic_reg ())
     pic_offset_table_rtx = gen_reg_rtx (Pmode);
 
-  hash_map<tree, tree> ssa_name_decls;
   for (i = 0; i < SA.map->num_partitions; i++)
     {
       tree var = partition_to_var (SA.map, i);
 
       gcc_assert (!virtual_operand_p (var));
 
-      /* Assign decls to each SSA name partition, share decls for partitions
-         we could have coalesced (those with the same type).  */
-      if (SSA_NAME_VAR (var) == NULL_TREE)
-	{
-	  tree *slot = &ssa_name_decls.get_or_insert (TREE_TYPE (var));
-	  if (!*slot)
-	    *slot = create_tmp_reg (TREE_TYPE (var));
-	  replace_ssa_name_symbol (var, *slot);
-	}
-
-      /* Always allocate space for partitions based on VAR_DECLs.  But for
-	 those based on PARM_DECLs or RESULT_DECLs and which matter for the
-	 debug info, there is no need to do so if optimization is disabled
-	 because all the SSA_NAMEs based on these DECLs have been coalesced
-	 into a single partition, which is thus assigned the canonical RTL
-	 location of the DECLs.  If in_lto_p, we can't rely on optimize,
-	 a function could be compiled with -O1 -flto first and only the
-	 link performed at -O0.  */
-      if (TREE_CODE (SSA_NAME_VAR (var)) == VAR_DECL)
-	expand_one_var (var, true, true);
-      else if (DECL_IGNORED_P (SSA_NAME_VAR (var)) || optimize || in_lto_p)
-	{
-	  /* This is a PARM_DECL or RESULT_DECL.  For those partitions that
-	     contain the default def (representing the parm or result itself)
-	     we don't do anything here.  But those which don't contain the
-	     default def (representing a temporary based on the parm/result)
-	     we need to allocate space just like for normal VAR_DECLs.  */
-	  if (!bitmap_bit_p (SA.partition_has_default_def, i))
-	    {
-	      expand_one_var (var, true, true);
-	      gcc_assert (SA.partition_to_pseudo[i]);
-	    }
-	}
+      expand_one_ssa_partition (var);
     }
 
+  for (i = 1; i < num_ssa_names; i++)
+    adjust_one_expanded_partition_var (ssa_name (i));
+
   if (flag_stack_protect == SPCT_FLAG_STRONG)
       gen_stack_protect_signal
 	= stack_protect_decl_p () || stack_protect_return_slot_p ();
@@ -5928,35 +6116,6 @@  pass_expand::execute (function *fun)
       parm_birth_insn = var_seq;
     }
 
-  /* Now that we also have the parameter RTXs, copy them over to our
-     partitions.  */
-  for (i = 0; i < SA.map->num_partitions; i++)
-    {
-      tree var = SSA_NAME_VAR (partition_to_var (SA.map, i));
-
-      if (TREE_CODE (var) != VAR_DECL
-	  && !SA.partition_to_pseudo[i])
-	SA.partition_to_pseudo[i] = DECL_RTL_IF_SET (var);
-      gcc_assert (SA.partition_to_pseudo[i]);
-
-      /* If this decl was marked as living in multiple places, reset
-	 this now to NULL.  */
-      if (DECL_RTL_IF_SET (var) == pc_rtx)
-	SET_DECL_RTL (var, NULL);
-
-      /* Some RTL parts really want to look at DECL_RTL(x) when x
-	 was a decl marked in REG_ATTR or MEM_ATTR.  We could use
-	 SET_DECL_RTL here making this available, but that would mean
-	 to select one of the potentially many RTLs for one DECL.  Instead
-	 of doing that we simply reset the MEM_EXPR of the RTL in question,
-	 then nobody can get at it and hence nobody can call DECL_RTL on it.  */
-      if (!DECL_RTL_SET_P (var))
-	{
-	  if (MEM_P (SA.partition_to_pseudo[i]))
-	    set_mem_expr (SA.partition_to_pseudo[i], NULL);
-	}
-    }
-
   /* If we have a class containing differently aligned pointers
      we need to merge those into the corresponding RTL pointer
      alignment.  */
@@ -5964,7 +6123,6 @@  pass_expand::execute (function *fun)
     {
       tree name = ssa_name (i);
       int part;
-      rtx r;
 
       if (!name
 	  /* We might have generated new SSA names in
@@ -5977,20 +6135,24 @@  pass_expand::execute (function *fun)
       if (part == NO_PARTITION)
 	continue;
 
-      /* Adjust all partition members to get the underlying decl of
-	 the representative which we might have created in expand_one_var.  */
-      if (SSA_NAME_VAR (name) == NULL_TREE)
+      gcc_assert (SA.partition_to_pseudo[part]);
+
+      /* If this decl was marked as living in multiple places, reset
+	 this now to NULL.  */
+      tree var = SSA_NAME_VAR (name);
+      if (var && DECL_RTL_IF_SET (var) == pc_rtx)
+	SET_DECL_RTL (var, NULL);
+      /* Check that the pseudos chosen by assign_parms are those of
+	 the corresponding default defs.  */
+      else if (SSA_NAME_IS_DEFAULT_DEF (name)
+	       && (TREE_CODE (var) == PARM_DECL
+		   || TREE_CODE (var) == RESULT_DECL))
 	{
-	  tree leader = partition_to_var (SA.map, part);
-	  gcc_assert (SSA_NAME_VAR (leader) != NULL_TREE);
-	  replace_ssa_name_symbol (name, SSA_NAME_VAR (leader));
+	  rtx in = DECL_RTL_IF_SET (var);
+	  gcc_assert (in);
+	  rtx out = SA.partition_to_pseudo[part];
+	  gcc_assert (in == out || rtx_equal_p (in, out));
 	}
-      if (!POINTER_TYPE_P (TREE_TYPE (name)))
-	continue;
-
-      r = SA.partition_to_pseudo[part];
-      if (REG_P (r))
-	mark_reg_pointer (r, get_pointer_alignment (name));
     }
 
   /* If this function is `main', emit a call to `__main'
diff --git a/gcc/cfgexpand.h b/gcc/cfgexpand.h
index a0b6e3e..602579d 100644
--- a/gcc/cfgexpand.h
+++ b/gcc/cfgexpand.h
@@ -22,5 +22,7 @@  along with GCC; see the file COPYING3.  If not see
 
 extern tree gimple_assign_rhs_to_tree (gimple);
 extern HOST_WIDE_INT estimated_stack_frame_size (struct cgraph_node *);
+extern rtx get_rtl_for_parm_ssa_default_def (tree var);
+
 
 #endif /* GCC_CFGEXPAND_H */
diff --git a/gcc/common.opt b/gcc/common.opt
index 8f25f8b..6d47e94 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2230,16 +2230,16 @@  Common Report Var(flag_tree_ch) Optimization
 Enable loop header copying on trees
 
 ftree-coalesce-inlined-vars
-Common Report Var(flag_ssa_coalesce_vars,1) Init(2) RejectNegative Optimization
-Enable coalescing of copy-related user variables that are inlined
+Common Ignore RejectNegative
+Does nothing.  Preserved for backward compatibility.
 
 ftree-coalesce-vars
-Common Report Var(flag_ssa_coalesce_vars,2) Optimization
-Enable coalescing of all copy-related user variables
+Common Report Var(flag_tree_coalesce_vars) Optimization
+Enable SSA coalescing of user variables
 
 ftree-copyrename
-Common Report Var(flag_tree_copyrename) Optimization
-Replace SSA temporaries with better names in copies
+Common Ignore
+Does nothing.  Preserved for backward compatibility.
 
 ftree-copy-prop
 Common Report Var(flag_tree_copy_prop) Optimization
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index a62c8b3..4b4ed2d 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -339,7 +339,6 @@  Objective-C and Objective-C++ Dialects}.
 -fdump-tree-phiprop@r{[}-@var{n}@r{]} @gol
 -fdump-tree-phiopt@r{[}-@var{n}@r{]} @gol
 -fdump-tree-forwprop@r{[}-@var{n}@r{]} @gol
--fdump-tree-copyrename@r{[}-@var{n}@r{]} @gol
 -fdump-tree-nrv -fdump-tree-vect @gol
 -fdump-tree-sink @gol
 -fdump-tree-sra@r{[}-@var{n}@r{]} @gol
@@ -445,9 +444,8 @@  Objective-C and Objective-C++ Dialects}.
 -fstack-protector-explicit -fstdarg-opt -fstrict-aliasing @gol
 -fstrict-overflow -fthread-jumps -ftracer -ftree-bit-ccp @gol
 -ftree-builtin-call-dce -ftree-ccp -ftree-ch @gol
--ftree-coalesce-inline-vars -ftree-coalesce-vars -ftree-copy-prop @gol
--ftree-copyrename -ftree-dce -ftree-dominator-opts -ftree-dse @gol
--ftree-forwprop -ftree-fre -ftree-loop-if-convert @gol
+-ftree-coalesce-vars -ftree-copy-prop -ftree-dce -ftree-dominator-opts @gol
+-ftree-dse -ftree-forwprop -ftree-fre -ftree-loop-if-convert @gol
 -ftree-loop-if-convert-stores -ftree-loop-im @gol
 -ftree-phiprop -ftree-loop-distribution -ftree-loop-distribute-patterns @gol
 -ftree-loop-ivcanon -ftree-loop-linear -ftree-loop-optimize @gol
@@ -7078,11 +7076,6 @@  name is made by appending @file{.phiopt} to the source file name.
 Dump each function after forward propagating single use variables.  The file
 name is made by appending @file{.forwprop} to the source file name.
 
-@item copyrename
-@opindex fdump-tree-copyrename
-Dump each function after applying the copy rename optimization.  The file
-name is made by appending @file{.copyrename} to the source file name.
-
 @item nrv
 @opindex fdump-tree-nrv
 Dump each function after applying the named return value optimization on
@@ -7547,8 +7540,8 @@  compilation time.
 -ftree-ccp @gol
 -fssa-phiopt @gol
 -ftree-ch @gol
+-ftree-coalesce-vars @gol
 -ftree-copy-prop @gol
--ftree-copyrename @gol
 -ftree-dce @gol
 -ftree-dominator-opts @gol
 -ftree-dse @gol
@@ -8812,6 +8805,15 @@  be parallelized.  Parallelize all the loops that can be analyzed to
 not contain loop carried dependences without checking that it is
 profitable to parallelize the loops.
 
+@item -ftree-coalesce-vars
+@opindex ftree-coalesce-vars
+Tell the compiler to attempt to combine small user-defined variables
+too, instead of just compiler temporaries.  This may severely limit the
+ability to debug an optimized program compiled with
+@option{-fno-var-tracking-assignments}.  In the negated form, this flag
+prevents SSA coalescing of user variables.  This option is enabled by
+default if optimization is enabled.
+
 @item -ftree-loop-if-convert
 @opindex ftree-loop-if-convert
 Attempt to transform conditional jumps in the innermost loops to
@@ -8925,32 +8927,6 @@  Perform scalar replacement of aggregates.  This pass replaces structure
 references with scalars to prevent committing structures to memory too
 early.  This flag is enabled by default at @option{-O} and higher.
 
-@item -ftree-copyrename
-@opindex ftree-copyrename
-Perform copy renaming on trees.  This pass attempts to rename compiler
-temporaries to other variables at copy locations, usually resulting in
-variable names which more closely resemble the original variables.  This flag
-is enabled by default at @option{-O} and higher.
-
-@item -ftree-coalesce-inlined-vars
-@opindex ftree-coalesce-inlined-vars
-Tell the copyrename pass (see @option{-ftree-copyrename}) to attempt to
-combine small user-defined variables too, but only if they are inlined
-from other functions.  It is a more limited form of
-@option{-ftree-coalesce-vars}.  This may harm debug information of such
-inlined variables, but it keeps variables of the inlined-into
-function apart from each other, such that they are more likely to
-contain the expected values in a debugging session.
-
-@item -ftree-coalesce-vars
-@opindex ftree-coalesce-vars
-Tell the copyrename pass (see @option{-ftree-copyrename}) to attempt to
-combine small user-defined variables too, instead of just compiler
-temporaries.  This may severely limit the ability to debug an optimized
-program compiled with @option{-fno-var-tracking-assignments}.  In the
-negated form, this flag prevents SSA coalescing of user variables,
-including inlined ones.  This option is enabled by default.
-
 @item -ftree-ter
 @opindex ftree-ter
 Perform temporary expression replacement during the SSA->normal phase.  Single
diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index ed2b30b..0648af6 100644
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -1232,6 +1232,9 @@  set_reg_attrs_for_parm (rtx parm_rtx, rtx mem)
 void
 set_reg_attrs_for_decl_rtl (tree t, rtx x)
 {
+  if (!t)
+    return;
+  tree tdecl = t;
   if (GET_CODE (x) == SUBREG)
     {
       gcc_assert (subreg_lowpart_p (x));
@@ -1240,7 +1243,7 @@  set_reg_attrs_for_decl_rtl (tree t, rtx x)
   if (REG_P (x))
     REG_ATTRS (x)
       = get_reg_attrs (t, byte_lowpart_offset (GET_MODE (x),
-					       DECL_MODE (t)));
+					       DECL_MODE (tdecl)));
   if (GET_CODE (x) == CONCAT)
     {
       if (REG_P (XEXP (x, 0)))
diff --git a/gcc/explow.c b/gcc/explow.c
index bd342c1..6941f4e 100644
--- a/gcc/explow.c
+++ b/gcc/explow.c
@@ -842,6 +842,35 @@  promote_decl_mode (const_tree decl, int *punsignedp)
   return pmode;
 }
 
+/* Return the promoted mode for name.  If it is a named SSA_NAME, it
+   is the same as promote_decl_mode.  Otherwise, it is the promoted
+   mode of a temp decl of same type as the SSA_NAME, if we had created
+   one.  */
+
+machine_mode
+promote_ssa_mode (const_tree name, int *punsignedp)
+{
+  gcc_assert (TREE_CODE (name) == SSA_NAME);
+
+  /* Partitions holding parms and results must be promoted as expected
+     by function.c.  */
+  if (SSA_NAME_VAR (name)
+      && (TREE_CODE (SSA_NAME_VAR (name)) == PARM_DECL
+	  || TREE_CODE (SSA_NAME_VAR (name)) == RESULT_DECL))
+    return promote_decl_mode (SSA_NAME_VAR (name), punsignedp);
+
+  tree type = TREE_TYPE (name);
+  int unsignedp = TYPE_UNSIGNED (type);
+  machine_mode mode = TYPE_MODE (type);
+
+  machine_mode pmode = promote_mode (type, mode, &unsignedp);
+  if (punsignedp)
+    *punsignedp = unsignedp;
+
+  return pmode;
+}
+
+
 
 /* Controls the behaviour of {anti_,}adjust_stack.  */
 static bool suppress_reg_args_size;
diff --git a/gcc/explow.h b/gcc/explow.h
index 94613de..52113db 100644
--- a/gcc/explow.h
+++ b/gcc/explow.h
@@ -57,6 +57,9 @@  extern machine_mode promote_mode (const_tree, machine_mode, int *);
 /* Return mode and signedness to use when object is promoted.  */
 machine_mode promote_decl_mode (const_tree, int *);
 
+/* Return mode and signedness to use when object is promoted.  */
+machine_mode promote_ssa_mode (const_tree, int *);
+
 /* Remove some bytes from the stack.  An rtx says how many.  */
 extern void adjust_stack (rtx);
 
diff --git a/gcc/expr.c b/gcc/expr.c
index 899a42c..d601129 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -9246,7 +9246,7 @@  expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
   rtx op0, op1, temp, decl_rtl;
   tree type;
   int unsignedp;
-  machine_mode mode;
+  machine_mode mode, dmode;
   enum tree_code code = TREE_CODE (exp);
   rtx subtarget, original_target;
   int ignore;
@@ -9377,7 +9377,8 @@  expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
       if (g == NULL
 	  && modifier == EXPAND_INITIALIZER
 	  && !SSA_NAME_IS_DEFAULT_DEF (exp)
-	  && (optimize || DECL_IGNORED_P (SSA_NAME_VAR (exp)))
+	  && (optimize || !SSA_NAME_VAR (exp)
+	      || DECL_IGNORED_P (SSA_NAME_VAR (exp)))
 	  && stmt_is_replaceable_p (SSA_NAME_DEF_STMT (exp)))
 	g = SSA_NAME_DEF_STMT (exp);
       if (g)
@@ -9456,15 +9457,18 @@  expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
       /* Ensure variable marked as used even if it doesn't go through
 	 a parser.  If it hasn't be used yet, write out an external
 	 definition.  */
-      TREE_USED (exp) = 1;
+      if (exp)
+	TREE_USED (exp) = 1;
 
       /* Show we haven't gotten RTL for this yet.  */
       temp = 0;
 
       /* Variables inherited from containing functions should have
 	 been lowered by this point.  */
-      context = decl_function_context (exp);
-      gcc_assert (SCOPE_FILE_SCOPE_P (context)
+      if (exp)
+	context = decl_function_context (exp);
+      gcc_assert (!exp
+		  || SCOPE_FILE_SCOPE_P (context)
 		  || context == current_function_decl
 		  || TREE_STATIC (exp)
 		  || DECL_EXTERNAL (exp)
@@ -9488,7 +9492,8 @@  expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
 	  decl_rtl = use_anchored_address (decl_rtl);
 	  if (modifier != EXPAND_CONST_ADDRESS
 	      && modifier != EXPAND_SUM
-	      && !memory_address_addr_space_p (DECL_MODE (exp),
+	      && !memory_address_addr_space_p (exp ? DECL_MODE (exp)
+					       : GET_MODE (decl_rtl),
 					       XEXP (decl_rtl, 0),
 					       MEM_ADDR_SPACE (decl_rtl)))
 	    temp = replace_equiv_address (decl_rtl,
@@ -9499,12 +9504,17 @@  expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
 	 if the address is a register.  */
       if (temp != 0)
 	{
-	  if (MEM_P (temp) && REG_P (XEXP (temp, 0)))
+	  if (exp && MEM_P (temp) && REG_P (XEXP (temp, 0)))
 	    mark_reg_pointer (XEXP (temp, 0), DECL_ALIGN (exp));
 
 	  return temp;
 	}
 
+      if (exp)
+	dmode = DECL_MODE (exp);
+      else
+	dmode = TYPE_MODE (TREE_TYPE (ssa_name));
+
       /* If the mode of DECL_RTL does not match that of the decl,
 	 there are two cases: we are dealing with a BLKmode value
 	 that is returned in a register, or we are dealing with
@@ -9512,22 +9522,23 @@  expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
 	 of the wanted mode, but mark it so that we know that it
 	 was already extended.  */
       if (REG_P (decl_rtl)
-	  && DECL_MODE (exp) != BLKmode
-	  && GET_MODE (decl_rtl) != DECL_MODE (exp))
+	  && dmode != BLKmode
+	  && GET_MODE (decl_rtl) != dmode)
 	{
 	  machine_mode pmode;
 
 	  /* Get the signedness to be used for this variable.  Ensure we get
 	     the same mode we got when the variable was declared.  */
-	  if (code == SSA_NAME
-	      && (g = SSA_NAME_DEF_STMT (ssa_name))
-	      && gimple_code (g) == GIMPLE_CALL
-	      && !gimple_call_internal_p (g))
+	  if (code != SSA_NAME)
+	    pmode = promote_decl_mode (exp, &unsignedp);
+	  else if ((g = SSA_NAME_DEF_STMT (ssa_name))
+		   && gimple_code (g) == GIMPLE_CALL
+		   && !gimple_call_internal_p (g))
 	    pmode = promote_function_mode (type, mode, &unsignedp,
 					   gimple_call_fntype (g),
 					   2);
 	  else
-	    pmode = promote_decl_mode (exp, &unsignedp);
+	    pmode = promote_ssa_mode (ssa_name, &unsignedp);
 	  gcc_assert (GET_MODE (decl_rtl) == pmode);
 
 	  temp = gen_lowpart_SUBREG (mode, decl_rtl);
diff --git a/gcc/function.c b/gcc/function.c
index f9d11bf4..c3d00cd 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -72,6 +72,9 @@  along with GCC; see the file COPYING3.  If not see
 #include "cfganal.h"
 #include "cfgbuild.h"
 #include "cfgcleanup.h"
+#include "cfgexpand.h"
+#include "basic-block.h"
+#include "df.h"
 #include "params.h"
 #include "bb-reorder.h"
 #include "shrink-wrap.h"
@@ -148,6 +151,8 @@  static bool contains (const_rtx, hash_table<insn_cache_hasher> *);
 static void prepare_function_start (void);
 static void do_clobber_return_reg (rtx, void *);
 static void do_use_return_reg (rtx, void *);
+static rtx rtl_for_parm (struct assign_parm_data_all *, tree);
+
 
 /* Stack of nested functions.  */
 /* Keep track of the cfun stack.  */
@@ -2105,6 +2110,30 @@  aggregate_value_p (const_tree exp, const_tree fntype)
 bool
 use_register_for_decl (const_tree decl)
 {
+  if (TREE_CODE (decl) == SSA_NAME)
+    {
+      /* We often try to use the SSA_NAME, instead of its underlying
+	 decl, to get type information and guide decisions, to avoid
+	 differences of behavior between anonymous and named
+	 variables, but in this one case we have to go for the actual
+	 variable if there is one.  The main reason is that, at least
+	 at -O0, we want to place user variables on the stack, but we
+	 don't mind using pseudos for anonymous or ignored temps.
+	 Should we take the SSA_NAME, we'd conclude all SSA_NAMEs
+	 should go in pseudos, whereas their corresponding variables
+	 might have to go on the stack.  So, disregarding the decl
+	 here would negatively impact debug info at -O0, enable
+	 coalescing between SSA_NAMEs that ought to get different
+	 stack/pseudo assignments, and get the incoming argument
+	 processing thoroughly confused by PARM_DECLs expected to live
+	 in stack slots but assigned to pseudos.  */
+      if (!SSA_NAME_VAR (decl))
+	return TYPE_MODE (TREE_TYPE (decl)) != BLKmode
+	  && !(flag_float_store && FLOAT_TYPE_P (TREE_TYPE (decl)));
+
+      decl = SSA_NAME_VAR (decl);
+    }
+
   if (!targetm.calls.allocate_stack_slots_for_args ())
     return true;
 
@@ -2240,7 +2269,7 @@  assign_parms_initialize_all (struct assign_parm_data_all *all)
    needed, else the old list.  */
 
 static void
-split_complex_args (vec<tree> *args)
+split_complex_args (struct assign_parm_data_all *all, vec<tree> *args)
 {
   unsigned i;
   tree p;
@@ -2251,6 +2280,7 @@  split_complex_args (vec<tree> *args)
       if (TREE_CODE (type) == COMPLEX_TYPE
 	  && targetm.calls.split_complex_arg (type))
 	{
+	  tree cparm = p;
 	  tree decl;
 	  tree subtype = TREE_TYPE (type);
 	  bool addressable = TREE_ADDRESSABLE (p);
@@ -2269,6 +2299,9 @@  split_complex_args (vec<tree> *args)
 	  DECL_ARTIFICIAL (p) = addressable;
 	  DECL_IGNORED_P (p) = addressable;
 	  TREE_ADDRESSABLE (p) = 0;
+	  /* Reset the RTL before layout_decl, or it may change the
+	     mode of the RTL of the original argument copied to P.  */
+	  SET_DECL_RTL (p, NULL_RTX);
 	  layout_decl (p, 0);
 	  (*args)[i] = p;
 
@@ -2280,6 +2313,25 @@  split_complex_args (vec<tree> *args)
 	  DECL_IGNORED_P (decl) = addressable;
 	  layout_decl (decl, 0);
 	  args->safe_insert (++i, decl);
+
+	  /* If we are expanding a function, rather than gimplifying
+	     it, propagate the RTL of the complex parm to the split
+	     declarations, and set their contexts so that
+	     maybe_reset_rtl_for_parm can recognize them and refrain
+	     from resetting their RTL.  */
+	  if (currently_expanding_to_rtl)
+	    {
+	      rtx rtl = rtl_for_parm (all, cparm);
+	      gcc_assert (!rtl || GET_CODE (rtl) == CONCAT);
+	      if (rtl)
+		{
+		  SET_DECL_RTL (p, XEXP (rtl, 0));
+		  SET_DECL_RTL (decl, XEXP (rtl, 1));
+
+		  DECL_CONTEXT (p) = cparm;
+		  DECL_CONTEXT (decl) = cparm;
+		}
+	    }
 	}
     }
 }
@@ -2342,7 +2394,7 @@  assign_parms_augmented_arg_list (struct assign_parm_data_all *all)
 
   /* If the target wants to split complex arguments into scalars, do so.  */
   if (targetm.calls.split_complex_arg)
-    split_complex_args (&fnargs);
+    split_complex_args (all, &fnargs);
 
   return fnargs;
 }
@@ -2745,23 +2797,98 @@  assign_parm_remove_parallels (struct assign_parm_data_one *data)
   data->entry_parm = entry_parm;
 }
 
+/* Wrapper for use_register_for_decl, that special-cases the
+   .result_ptr as the function's RESULT_DECL when the RESULT_DECL is
+   passed by reference.  */
+
+static bool
+use_register_for_parm_decl (struct assign_parm_data_all *all, tree parm)
+{
+  if (parm == all->function_result_decl)
+    {
+      tree result = DECL_RESULT (current_function_decl);
+
+      if (DECL_BY_REFERENCE (result))
+	parm = result;
+    }
+
+  return use_register_for_decl (parm);
+}
+
+/* Wrapper for get_rtl_for_parm_ssa_default_def, that special-cases
+   the .result_ptr as the function's RESULT_DECL when the RESULT_DECL
+   is passed by reference.  */
+
+static rtx
+rtl_for_parm (struct assign_parm_data_all *all, tree parm)
+{
+  if (parm == all->function_result_decl)
+    {
+      tree result = DECL_RESULT (current_function_decl);
+
+      if (!DECL_BY_REFERENCE (result))
+	return NULL_RTX;
+
+      parm = result;
+    }
+
+  return get_rtl_for_parm_ssa_default_def (parm);
+}
+
+/* Reset the location of PARM_DECLs and RESULT_DECLs that had
+   SSA_NAMEs in multiple partitions, so that assign_parms will choose
+   the default def, if it exists, or create new RTL to hold the unused
+   entry value.  If we are coalescing across variables, we want to
+   reset the location too, because a parm without a default def
+   (incoming value unused) might be coalesced with one with a default
+   def, and then assign_parms would copy both incoming values to the
+   same location, which might cause the wrong value to survive.  */
+static void
+maybe_reset_rtl_for_parm (tree parm)
+{
+  gcc_assert (TREE_CODE (parm) == PARM_DECL
+	      || TREE_CODE (parm) == RESULT_DECL);
+
+  /* This is a split complex parameter, and its context was set to its
+     original PARM_DECL in split_complex_args so that we could
+     recognize it here and not reset its RTL.  */
+  if (DECL_CONTEXT (parm) && TREE_CODE (DECL_CONTEXT (parm)) == PARM_DECL)
+    {
+      DECL_CONTEXT (parm) = DECL_CONTEXT (DECL_CONTEXT (parm));
+      return;
+    }
+
+  if ((flag_tree_coalesce_vars
+       || (DECL_RTL_SET_P (parm) && DECL_RTL (parm) == pc_rtx))
+      && is_gimple_reg (parm))
+    SET_DECL_RTL (parm, NULL_RTX);
+}
+
 /* A subroutine of assign_parms.  Adjust DATA->STACK_RTL such that it's
    always valid and properly aligned.  */
 
 static void
-assign_parm_adjust_stack_rtl (struct assign_parm_data_one *data)
+assign_parm_adjust_stack_rtl (struct assign_parm_data_all *all, tree parm,
+			      struct assign_parm_data_one *data)
 {
   rtx stack_parm = data->stack_parm;
 
+  /* If out-of-SSA assigned RTL to the parm default def, make sure we
+     don't use what we might have computed before.  */
+  rtx ssa_assigned = rtl_for_parm (all, parm);
+  if (ssa_assigned)
+    stack_parm = NULL;
+
   /* If we can't trust the parm stack slot to be aligned enough for its
      ultimate type, don't use that slot after entry.  We'll make another
      stack slot, if we need one.  */
-  if (stack_parm
-      && ((STRICT_ALIGNMENT
-	   && GET_MODE_ALIGNMENT (data->nominal_mode) > MEM_ALIGN (stack_parm))
-	  || (data->nominal_type
-	      && TYPE_ALIGN (data->nominal_type) > MEM_ALIGN (stack_parm)
-	      && MEM_ALIGN (stack_parm) < PREFERRED_STACK_BOUNDARY)))
+  else if (stack_parm
+	   && ((STRICT_ALIGNMENT
+		&& (GET_MODE_ALIGNMENT (data->nominal_mode)
+		    > MEM_ALIGN (stack_parm)))
+	       || (data->nominal_type
+		   && TYPE_ALIGN (data->nominal_type) > MEM_ALIGN (stack_parm)
+		   && MEM_ALIGN (stack_parm) < PREFERRED_STACK_BOUNDARY)))
     stack_parm = NULL;
 
   /* If parm was passed in memory, and we need to convert it on entry,
@@ -2823,14 +2950,21 @@  assign_parm_setup_block (struct assign_parm_data_all *all,
 
   size = int_size_in_bytes (data->passed_type);
   size_stored = CEIL_ROUND (size, UNITS_PER_WORD);
+
   if (stack_parm == 0)
     {
       DECL_ALIGN (parm) = MAX (DECL_ALIGN (parm), BITS_PER_WORD);
-      stack_parm = assign_stack_local (BLKmode, size_stored,
-				       DECL_ALIGN (parm));
-      if (GET_MODE_SIZE (GET_MODE (entry_parm)) == size)
-	PUT_MODE (stack_parm, GET_MODE (entry_parm));
-      set_mem_attributes (stack_parm, parm, 1);
+      stack_parm = rtl_for_parm (all, parm);
+      if (stack_parm)
+	stack_parm = copy_rtx (stack_parm);
+      else
+	{
+	  stack_parm = assign_stack_local (BLKmode, size_stored,
+					   DECL_ALIGN (parm));
+	  if (GET_MODE_SIZE (GET_MODE (entry_parm)) == size)
+	    PUT_MODE (stack_parm, GET_MODE (entry_parm));
+	  set_mem_attributes (stack_parm, parm, 1);
+	}
     }
 
   /* If a BLKmode arrives in registers, copy it to a stack slot.  Handle
@@ -2968,10 +3102,19 @@  assign_parm_setup_reg (struct assign_parm_data_all *all, tree parm,
     = promote_function_mode (data->nominal_type, data->nominal_mode, &unsignedp,
 			     TREE_TYPE (current_function_decl), 2);
 
-  parmreg = gen_reg_rtx (promoted_nominal_mode);
+  rtx from_expand = rtl_for_parm (all, parm);
 
-  if (!DECL_ARTIFICIAL (parm))
-    mark_user_reg (parmreg);
+  if (from_expand && !data->passed_pointer)
+    {
+      parmreg = from_expand;
+      gcc_assert (GET_MODE (parmreg) == promoted_nominal_mode);
+    }
+  else
+    {
+      parmreg = gen_reg_rtx (promoted_nominal_mode);
+      if (!DECL_ARTIFICIAL (parm))
+	mark_user_reg (parmreg);
+    }
 
   /* If this was an item that we received a pointer to,
      set DECL_RTL appropriately.  */
@@ -2990,6 +3133,8 @@  assign_parm_setup_reg (struct assign_parm_data_all *all, tree parm,
      assign_parm_find_data_types and expand_expr_real_1.  */
 
   equiv_stack_parm = data->stack_parm;
+  if (!equiv_stack_parm)
+    equiv_stack_parm = data->entry_parm;
   validated_mem = validize_mem (copy_rtx (data->entry_parm));
 
   need_conversion = (data->nominal_mode != data->passed_mode
@@ -3130,11 +3275,17 @@  assign_parm_setup_reg (struct assign_parm_data_all *all, tree parm,
 
   /* If we were passed a pointer but the actual value can safely live
      in a register, retrieve it and use it directly.  */
-  if (data->passed_pointer && TYPE_MODE (TREE_TYPE (parm)) != BLKmode)
+  if (data->passed_pointer
+      && (from_expand || TYPE_MODE (TREE_TYPE (parm)) != BLKmode))
     {
       /* We can't use nominal_mode, because it will have been set to
 	 Pmode above.  We must use the actual mode of the parm.  */
-      if (use_register_for_decl (parm))
+      if (from_expand)
+	{
+	  parmreg = from_expand;
+	  gcc_assert (GET_MODE (parmreg) == TYPE_MODE (TREE_TYPE (parm)));
+	}
+      else if (use_register_for_decl (parm))
 	{
 	  parmreg = gen_reg_rtx (TYPE_MODE (TREE_TYPE (parm)));
 	  mark_user_reg (parmreg);
@@ -3174,7 +3325,7 @@  assign_parm_setup_reg (struct assign_parm_data_all *all, tree parm,
 
       /* STACK_PARM is the pointer, not the parm, and PARMREG is
 	 now the parm.  */
-      data->stack_parm = NULL;
+      data->stack_parm = equiv_stack_parm = NULL;
     }
 
   /* Mark the register as eliminable if we did no conversion and it was
@@ -3184,11 +3335,11 @@  assign_parm_setup_reg (struct assign_parm_data_all *all, tree parm,
      make here would screw up life analysis for it.  */
   if (data->nominal_mode == data->passed_mode
       && !did_conversion
-      && data->stack_parm != 0
-      && MEM_P (data->stack_parm)
+      && equiv_stack_parm != 0
+      && MEM_P (equiv_stack_parm)
       && data->locate.offset.var == 0
       && reg_mentioned_p (virtual_incoming_args_rtx,
-			  XEXP (data->stack_parm, 0)))
+			  XEXP (equiv_stack_parm, 0)))
     {
       rtx_insn *linsn = get_last_insn ();
       rtx_insn *sinsn;
@@ -3201,8 +3352,8 @@  assign_parm_setup_reg (struct assign_parm_data_all *all, tree parm,
 	    = GET_MODE_INNER (GET_MODE (parmreg));
 	  int regnor = REGNO (XEXP (parmreg, 0));
 	  int regnoi = REGNO (XEXP (parmreg, 1));
-	  rtx stackr = adjust_address_nv (data->stack_parm, submode, 0);
-	  rtx stacki = adjust_address_nv (data->stack_parm, submode,
+	  rtx stackr = adjust_address_nv (equiv_stack_parm, submode, 0);
+	  rtx stacki = adjust_address_nv (equiv_stack_parm, submode,
 					  GET_MODE_SIZE (submode));
 
 	  /* Scan backwards for the set of the real and
@@ -3275,6 +3426,13 @@  assign_parm_setup_stack (struct assign_parm_data_all *all, tree parm,
 
       if (data->stack_parm == 0)
 	{
+	  rtx x = data->stack_parm = rtl_for_parm (all, parm);
+	  if (x)
+	    gcc_assert (GET_MODE (x) == GET_MODE (data->entry_parm));
+	}
+
+      if (data->stack_parm == 0)
+	{
 	  int align = STACK_SLOT_ALIGNMENT (data->passed_type,
 					    GET_MODE (data->entry_parm),
 					    TYPE_ALIGN (data->passed_type));
@@ -3531,6 +3689,8 @@  assign_parms (tree fndecl)
 	  DECL_INCOMING_RTL (parm) = DECL_RTL (parm);
 	  continue;
 	}
+      else
+	maybe_reset_rtl_for_parm (parm);
 
       /* Estimate stack alignment from parameter alignment.  */
       if (SUPPORTS_STACK_ALIGNMENT)
@@ -3580,7 +3740,9 @@  assign_parms (tree fndecl)
       else
 	set_decl_incoming_rtl (parm, data.entry_parm, false);
 
-      /* Boudns should be loaded in the particular order to
+      assign_parm_adjust_stack_rtl (&all, parm, &data);
+
+      /* Bounds should be loaded in the particular order to
 	 have registers allocated correctly.  Collect info about
 	 input bounds and load them later.  */
       if (POINTER_BOUNDS_TYPE_P (data.passed_type))
@@ -3597,11 +3759,10 @@  assign_parms (tree fndecl)
 	}
       else
 	{
-	  assign_parm_adjust_stack_rtl (&data);
-
 	  if (assign_parm_setup_block_p (&data))
 	    assign_parm_setup_block (&all, parm, &data);
-	  else if (data.passed_pointer || use_register_for_decl (parm))
+	  else if (data.passed_pointer
+		   || use_register_for_parm_decl (&all, parm))
 	    assign_parm_setup_reg (&all, parm, &data);
 	  else
 	    assign_parm_setup_stack (&all, parm, &data);
@@ -4932,7 +5093,9 @@  expand_function_start (tree subr)
      before any library calls that assign parms might generate.  */
 
   /* Decide whether to return the value in memory or in a register.  */
-  if (aggregate_value_p (DECL_RESULT (subr), subr))
+  tree res = DECL_RESULT (subr);
+  maybe_reset_rtl_for_parm (res);
+  if (aggregate_value_p (res, subr))
     {
       /* Returning something that won't go in a register.  */
       rtx value_address = 0;
@@ -4940,7 +5103,7 @@  expand_function_start (tree subr)
 #ifdef PCC_STATIC_STRUCT_RETURN
       if (cfun->returns_pcc_struct)
 	{
-	  int size = int_size_in_bytes (TREE_TYPE (DECL_RESULT (subr)));
+	  int size = int_size_in_bytes (TREE_TYPE (res));
 	  value_address = assemble_static_space (size);
 	}
       else
@@ -4952,36 +5115,45 @@  expand_function_start (tree subr)
 	     it.  */
 	  if (sv)
 	    {
-	      value_address = gen_reg_rtx (Pmode);
+	      if (DECL_BY_REFERENCE (res))
+		value_address = get_rtl_for_parm_ssa_default_def (res);
+	      if (!value_address)
+		value_address = gen_reg_rtx (Pmode);
 	      emit_move_insn (value_address, sv);
 	    }
 	}
       if (value_address)
 	{
 	  rtx x = value_address;
-	  if (!DECL_BY_REFERENCE (DECL_RESULT (subr)))
+	  if (!DECL_BY_REFERENCE (res))
 	    {
-	      x = gen_rtx_MEM (DECL_MODE (DECL_RESULT (subr)), x);
-	      set_mem_attributes (x, DECL_RESULT (subr), 1);
+	      x = get_rtl_for_parm_ssa_default_def (res);
+	      if (!x)
+		{
+		  x = gen_rtx_MEM (DECL_MODE (res), value_address);
+		  set_mem_attributes (x, res, 1);
+		}
 	    }
-	  SET_DECL_RTL (DECL_RESULT (subr), x);
+	  SET_DECL_RTL (res, x);
 	}
     }
-  else if (DECL_MODE (DECL_RESULT (subr)) == VOIDmode)
+  else if (DECL_MODE (res) == VOIDmode)
     /* If return mode is void, this decl rtl should not be used.  */
-    SET_DECL_RTL (DECL_RESULT (subr), NULL_RTX);
+    SET_DECL_RTL (res, NULL_RTX);
   else
     {
       /* Compute the return values into a pseudo reg, which we will copy
 	 into the true return register after the cleanups are done.  */
-      tree return_type = TREE_TYPE (DECL_RESULT (subr));
-      if (TYPE_MODE (return_type) != BLKmode
-	  && targetm.calls.return_in_msb (return_type))
+      tree return_type = TREE_TYPE (res);
+      rtx x = get_rtl_for_parm_ssa_default_def (res);
+      if (x)
+	/* Use it.  */;
+      else if (TYPE_MODE (return_type) != BLKmode
+	       && targetm.calls.return_in_msb (return_type))
 	/* expand_function_end will insert the appropriate padding in
 	   this case.  Use the return value's natural (unpadded) mode
 	   within the function proper.  */
-	SET_DECL_RTL (DECL_RESULT (subr),
-		      gen_reg_rtx (TYPE_MODE (return_type)));
+	x = gen_reg_rtx (TYPE_MODE (return_type));
       else
 	{
 	  /* In order to figure out what mode to use for the pseudo, we
@@ -4992,25 +5164,26 @@  expand_function_start (tree subr)
 	  /* Structures that are returned in registers are not
 	     aggregate_value_p, so we may see a PARALLEL or a REG.  */
 	  if (REG_P (hard_reg))
-	    SET_DECL_RTL (DECL_RESULT (subr),
-			  gen_reg_rtx (GET_MODE (hard_reg)));
+	    x = gen_reg_rtx (GET_MODE (hard_reg));
 	  else
 	    {
 	      gcc_assert (GET_CODE (hard_reg) == PARALLEL);
-	      SET_DECL_RTL (DECL_RESULT (subr), gen_group_rtx (hard_reg));
+	      x = gen_group_rtx (hard_reg);
 	    }
 	}
 
+      SET_DECL_RTL (res, x);
+
       /* Set DECL_REGISTER flag so that expand_function_end will copy the
 	 result to the real return register(s).  */
-      DECL_REGISTER (DECL_RESULT (subr)) = 1;
+      DECL_REGISTER (res) = 1;
 
       if (chkp_function_instrumented_p (current_function_decl))
 	{
-	  tree return_type = TREE_TYPE (DECL_RESULT (subr));
+	  tree return_type = TREE_TYPE (res);
 	  rtx bounds = targetm.calls.chkp_function_value_bounds (return_type,
 								 subr, 1);
-	  SET_DECL_BOUNDS_RTL (DECL_RESULT (subr), bounds);
+	  SET_DECL_BOUNDS_RTL (res, bounds);
 	}
     }
 
@@ -5025,7 +5198,9 @@  expand_function_start (tree subr)
       rtx local, chain;
      rtx_insn *insn;
 
-      local = gen_reg_rtx (Pmode);
+      local = get_rtl_for_parm_ssa_default_def (parm);
+      if (!local)
+	local = gen_reg_rtx (Pmode);
       chain = targetm.calls.static_chain (current_function_decl, true);
 
       set_decl_incoming_rtl (parm, chain, false);
diff --git a/gcc/gimple-expr.c b/gcc/gimple-expr.c
index b558d90..baed630 100644
--- a/gcc/gimple-expr.c
+++ b/gcc/gimple-expr.c
@@ -375,45 +375,6 @@  copy_var_decl (tree var, tree name, tree type)
   return copy;
 }
 
-/* Given SSA_NAMEs NAME1 and NAME2, return true if they are candidates for
-   coalescing together, false otherwise.
-
-   This must stay consistent with var_map_base_init in tree-ssa-live.c.  */
-
-bool
-gimple_can_coalesce_p (tree name1, tree name2)
-{
-  /* First check the SSA_NAME's associated DECL.  We only want to
-     coalesce if they have the same DECL or both have no associated DECL.  */
-  tree var1 = SSA_NAME_VAR (name1);
-  tree var2 = SSA_NAME_VAR (name2);
-  var1 = (var1 && (!VAR_P (var1) || !DECL_IGNORED_P (var1))) ? var1 : NULL_TREE;
-  var2 = (var2 && (!VAR_P (var2) || !DECL_IGNORED_P (var2))) ? var2 : NULL_TREE;
-  if (var1 != var2)
-    return false;
-
-  /* Now check the types.  If the types are the same, then we should
-     try to coalesce V1 and V2.  */
-  tree t1 = TREE_TYPE (name1);
-  tree t2 = TREE_TYPE (name2);
-  if (t1 == t2)
-    return true;
-
-  /* If the types are not the same, check for a canonical type match.  This
-     (for example) allows coalescing when the types are fundamentally the
-     same, but just have different names. 
-
-     Note pointer types with different address spaces may have the same
-     canonical type.  Those are rejected for coalescing by the
-     types_compatible_p check.  */
-  if (TYPE_CANONICAL (t1)
-      && TYPE_CANONICAL (t1) == TYPE_CANONICAL (t2)
-      && types_compatible_p (t1, t2))
-    return true;
-
-  return false;
-}
-
 /* Strip off a legitimate source ending from the input string NAME of
    length LEN.  Rather than having to know the names used by all of
    our front ends, we strip off an ending of a period followed by
diff --git a/gcc/gimple-expr.h b/gcc/gimple-expr.h
index ed23eb2..3d1c89f 100644
--- a/gcc/gimple-expr.h
+++ b/gcc/gimple-expr.h
@@ -28,7 +28,6 @@  extern gimple_seq gimple_body (tree);
 extern bool gimple_has_body_p (tree);
 extern const char *gimple_decl_printable_name (tree, int);
 extern tree copy_var_decl (tree, tree, tree);
-extern bool gimple_can_coalesce_p (tree, tree);
 extern tree create_tmp_var_name (const char *);
 extern tree create_tmp_var_raw (tree, const char * = NULL);
 extern tree create_tmp_var (tree, const char * = NULL);
diff --git a/gcc/opts.c b/gcc/opts.c
index 468a802..f22edd3 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -445,12 +445,12 @@  static const struct default_options default_options_table[] =
     { OPT_LEVELS_1_PLUS, OPT_fsplit_wide_types, NULL, 1 },
     { OPT_LEVELS_1_PLUS, OPT_ftree_ccp, NULL, 1 },
     { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_ftree_bit_ccp, NULL, 1 },
+    { OPT_LEVELS_1_PLUS, OPT_ftree_coalesce_vars, NULL, 1 },
     { OPT_LEVELS_1_PLUS, OPT_ftree_dce, NULL, 1 },
     { OPT_LEVELS_1_PLUS, OPT_ftree_dominator_opts, NULL, 1 },
     { OPT_LEVELS_1_PLUS, OPT_ftree_dse, NULL, 1 },
     { OPT_LEVELS_1_PLUS, OPT_ftree_ter, NULL, 1 },
     { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_ftree_sra, NULL, 1 },
-    { OPT_LEVELS_1_PLUS, OPT_ftree_copyrename, NULL, 1 },
     { OPT_LEVELS_1_PLUS, OPT_ftree_fre, NULL, 1 },
     { OPT_LEVELS_1_PLUS, OPT_ftree_copy_prop, NULL, 1 },
     { OPT_LEVELS_1_PLUS, OPT_ftree_sink, NULL, 1 },
diff --git a/gcc/passes.def b/gcc/passes.def
index 6b66f8f..64fc4d9 100644
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -77,7 +77,6 @@  along with GCC; see the file COPYING3.  If not see
       NEXT_PASS (pass_all_early_optimizations);
       PUSH_INSERT_PASSES_WITHIN (pass_all_early_optimizations)
 	  NEXT_PASS (pass_remove_cgraph_callee_edges);
-	  NEXT_PASS (pass_rename_ssa_copies);
 	  NEXT_PASS (pass_object_sizes);
 	  NEXT_PASS (pass_ccp);
 	  /* After CCP we rewrite no longer addressed locals into SSA
@@ -155,7 +154,6 @@  along with GCC; see the file COPYING3.  If not see
       /* Initial scalar cleanups before alias computation.
 	 They ensure memory accesses are not indirect wherever possible.  */
       NEXT_PASS (pass_strip_predict_hints);
-      NEXT_PASS (pass_rename_ssa_copies);
       NEXT_PASS (pass_ccp);
       /* After CCP we rewrite no longer addressed locals into SSA
 	 form if possible.  */
@@ -183,7 +181,6 @@  along with GCC; see the file COPYING3.  If not see
       NEXT_PASS (pass_ch);
       NEXT_PASS (pass_lower_complex);
       NEXT_PASS (pass_sra);
-      NEXT_PASS (pass_rename_ssa_copies);
       /* The dom pass will also resolve all __builtin_constant_p calls
          that are still there to 0.  This has to be done after some
 	 propagations have already run, but before some more dead code
@@ -293,7 +290,6 @@  along with GCC; see the file COPYING3.  If not see
       NEXT_PASS (pass_fold_builtins);
       NEXT_PASS (pass_optimize_widening_mul);
       NEXT_PASS (pass_tail_calls);
-      NEXT_PASS (pass_rename_ssa_copies);
       /* FIXME: If DCE is not run before checking for uninitialized uses,
 	 we may get false warnings (e.g., testsuite/gcc.dg/uninit-5.c).
 	 However, this also causes us to misdiagnose cases that should be
@@ -328,7 +324,6 @@  along with GCC; see the file COPYING3.  If not see
       NEXT_PASS (pass_dce);
       NEXT_PASS (pass_asan);
       NEXT_PASS (pass_tsan);
-      NEXT_PASS (pass_rename_ssa_copies);
       /* ???  We do want some kind of loop invariant motion, but we possibly
          need to adjust LIM to be more friendly towards preserving accurate
 	 debug information here.  */
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 0d4f4a4..288227a 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -794,7 +794,8 @@  layout_decl (tree decl, unsigned int known_align)
     {
       PUT_MODE (rtl, DECL_MODE (decl));
       SET_DECL_RTL (decl, 0);
-      set_mem_attributes (rtl, decl, 1);
+      if (MEM_P (rtl))
+	set_mem_attributes (rtl, decl, 1);
       SET_DECL_RTL (decl, rtl);
     }
 }
diff --git a/gcc/testsuite/gcc.dg/guality/pr54200.c b/gcc/testsuite/gcc.dg/guality/pr54200.c
index 9b17187..e1e7293 100644
--- a/gcc/testsuite/gcc.dg/guality/pr54200.c
+++ b/gcc/testsuite/gcc.dg/guality/pr54200.c
@@ -1,6 +1,6 @@ 
 /* PR tree-optimization/54200 */
 /* { dg-do run } */
-/* { dg-options "-g -fno-var-tracking-assignments" } */
+/* { dg-options "-g -fno-var-tracking-assignments -fno-tree-coalesce-vars" } */
 
 int o __attribute__((used));
 
diff --git a/gcc/testsuite/gcc.dg/ssp-1.c b/gcc/testsuite/gcc.dg/ssp-1.c
index 5467f4d..db69332 100644
--- a/gcc/testsuite/gcc.dg/ssp-1.c
+++ b/gcc/testsuite/gcc.dg/ssp-1.c
@@ -12,7 +12,7 @@  __stack_chk_fail (void)
 
 int main ()
 {
-  int i;
+  register int i;
   char foo[255];
 
   // smash stack
diff --git a/gcc/testsuite/gcc.dg/ssp-2.c b/gcc/testsuite/gcc.dg/ssp-2.c
index 9a7ac32..752fe53 100644
--- a/gcc/testsuite/gcc.dg/ssp-2.c
+++ b/gcc/testsuite/gcc.dg/ssp-2.c
@@ -14,7 +14,7 @@  __stack_chk_fail (void)
 void
 overflow()
 {
-  int i = 0;
+  register int i = 0;
   char foo[30];
 
   /* Overflow buffer.  */
diff --git a/gcc/testsuite/gcc.dg/torture/parm-coalesce.c b/gcc/testsuite/gcc.dg/torture/parm-coalesce.c
new file mode 100644
index 0000000..dbd81c1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/parm-coalesce.c
@@ -0,0 +1,40 @@ 
+/* { dg-do run } */
+
+#include <stdlib.h>
+
+/* Make sure we don't coalesce both incoming parms, one whose incoming
+   value is unused, to the same location, so as to overwrite one of
+   them with the incoming value of the other.  */
+
+int __attribute__((noinline, noclone))
+foo (int i, int j)
+{
+  j = i; /* The incoming value for J is unused.  */
+  i = 2;
+  if (j)
+    j++;
+  j += i + 1;
+  return j;
+}
+
+/* Same as foo, but with swapped parameters.  */
+int __attribute__((noinline, noclone))
+bar (int j, int i)
+{
+  j = i; /* The incoming value for J is unused.  */
+  i = 2;
+  if (j)
+    j++;
+  j += i + 1;
+  return j;
+}
+
+int
+main (void)
+{
+  if (foo (0, 1) != 3)
+    abort ();
+  if (bar (1, 0) != 3)
+    abort ();
+  return 0;
+}
diff --git a/gcc/tree-outof-ssa.c b/gcc/tree-outof-ssa.c
index 7b747ab9..978476c 100644
--- a/gcc/tree-outof-ssa.c
+++ b/gcc/tree-outof-ssa.c
@@ -279,7 +279,6 @@  insert_value_copy_on_edge (edge e, int dest, tree src, source_location locus)
   rtx dest_rtx, seq, x;
   machine_mode dest_mode, src_mode;
   int unsignedp;
-  tree var;
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
@@ -301,12 +300,12 @@  insert_value_copy_on_edge (edge e, int dest, tree src, source_location locus)
 
   start_sequence ();
 
-  var = SSA_NAME_VAR (partition_to_var (SA.map, dest));
+  tree name = partition_to_var (SA.map, dest);
   src_mode = TYPE_MODE (TREE_TYPE (src));
   dest_mode = GET_MODE (dest_rtx);
-  gcc_assert (src_mode == TYPE_MODE (TREE_TYPE (var)));
+  gcc_assert (src_mode == TYPE_MODE (TREE_TYPE (name)));
   gcc_assert (!REG_P (dest_rtx)
-	      || dest_mode == promote_decl_mode (var, &unsignedp));
+	      || dest_mode == promote_ssa_mode (name, &unsignedp));
 
   if (src_mode != dest_mode)
     {
@@ -682,13 +681,12 @@  elim_backward (elim_graph g, int T)
 static rtx
 get_temp_reg (tree name)
 {
-  tree var = TREE_CODE (name) == SSA_NAME ? SSA_NAME_VAR (name) : name;
-  tree type = TREE_TYPE (var);
+  tree type = TREE_TYPE (name);
   int unsignedp;
-  machine_mode reg_mode = promote_decl_mode (var, &unsignedp);
+  machine_mode reg_mode = promote_ssa_mode (name, &unsignedp);
   rtx x = gen_reg_rtx (reg_mode);
   if (POINTER_TYPE_P (type))
-    mark_reg_pointer (x, TYPE_ALIGN (TREE_TYPE (TREE_TYPE (var))));
+    mark_reg_pointer (x, TYPE_ALIGN (TREE_TYPE (type)));
   return x;
 }
 
@@ -988,7 +986,7 @@  remove_ssa_form (bool perform_ter, struct ssaexpand *sa)
 
   /* Return to viewing the variable list as just all reference variables after
      coalescing has been performed.  */
-  partition_view_normal (map, false);
+  partition_view_normal (map);
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
diff --git a/gcc/tree-ssa-coalesce.c b/gcc/tree-ssa-coalesce.c
index bf8983f..a622728 100644
--- a/gcc/tree-ssa-coalesce.c
+++ b/gcc/tree-ssa-coalesce.c
@@ -36,6 +36,7 @@  along with GCC; see the file COPYING3.  If not see
 #include "gimple-iterator.h"
 #include "tree-ssa-live.h"
 #include "tree-ssa-coalesce.h"
+#include "explow.h"
 #include "diagnostic-core.h"
 
 
@@ -806,6 +807,16 @@  build_ssa_conflict_graph (tree_live_info_p liveinfo)
   basic_block bb;
   ssa_op_iter iter;
   live_track_p live;
+  basic_block entry;
+
+  /* If inter-variable coalescing is enabled, we may attempt to
+     coalesce variables from different base variables, including
+     different parameters, so we have to make sure default defs live
+     at the entry block conflict with each other.  */
+  if (flag_tree_coalesce_vars)
+    entry = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun));
+  else
+    entry = NULL;
 
   map = live_var_map (liveinfo);
   graph = ssa_conflicts_new (num_var_partitions (map));
@@ -864,6 +875,30 @@  build_ssa_conflict_graph (tree_live_info_p liveinfo)
 	    live_track_process_def (live, result, graph);
 	}
 
+      /* Pretend there are defs for params' default defs at the start
+	 of the (post-)entry block.  */
+      if (bb == entry)
+	{
+	  unsigned base;
+	  bitmap_iterator bi;
+	  EXECUTE_IF_SET_IN_BITMAP (live->live_base_var, 0, base, bi)
+	    {
+	      bitmap_iterator bi2;
+	      unsigned part;
+	      EXECUTE_IF_SET_IN_BITMAP (live->live_base_partitions[base],
+					0, part, bi2)
+		{
+		  tree var = partition_to_var (map, part);
+		  if (!SSA_NAME_VAR (var)
+		      || (TREE_CODE (SSA_NAME_VAR (var)) != PARM_DECL
+			  && TREE_CODE (SSA_NAME_VAR (var)) != RESULT_DECL)
+		      || !SSA_NAME_IS_DEFAULT_DEF (var))
+		    continue;
+		  live_track_process_def (live, var, graph);
+		}
+	    }
+	}
+
      live_track_clear_base_vars (live);
     }
 
@@ -1132,6 +1167,7 @@  attempt_coalesce (var_map map, ssa_conflicts_p graph, int x, int y,
     {
       var1 = partition_to_var (map, p1);
       var2 = partition_to_var (map, p2);
+
       z = var_union (map, var1, var2);
       if (z == NO_PARTITION)
 	{
@@ -1149,6 +1185,7 @@  attempt_coalesce (var_map map, ssa_conflicts_p graph, int x, int y,
 
       if (debug)
 	fprintf (debug, ": Success -> %d\n", z);
+
       return true;
     }
 
@@ -1244,6 +1281,328 @@  ssa_name_var_hash::equal (const tree_node *n1, const tree_node *n2)
 }
 
 
+/* Output partition map MAP with coalescing plan PART to file F.  */
+
+void
+dump_part_var_map (FILE *f, partition part, var_map map)
+{
+  int t;
+  unsigned x, y;
+  int p;
+
+  fprintf (f, "\nCoalescible Partition map \n\n");
+
+  for (x = 0; x < map->num_partitions; x++)
+    {
+      if (map->view_to_partition != NULL)
+	p = map->view_to_partition[x];
+      else
+	p = x;
+
+      if (ssa_name (p) == NULL_TREE
+	  || virtual_operand_p (ssa_name (p)))
+        continue;
+
+      t = 0;
+      for (y = 1; y < num_ssa_names; y++)
+        {
+	  tree var = version_to_var (map, y);
+	  if (!var)
+	    continue;
+	  int q = var_to_partition (map, var);
+	  p = partition_find (part, q);
+	  gcc_assert (map->partition_to_base_index[q]
+		      == map->partition_to_base_index[p]);
+
+	  if (p == (int)x)
+	    {
+	      if (t++ == 0)
+	        {
+		  fprintf (f, "Partition %d, base %d (", x,
+			   map->partition_to_base_index[q]);
+		  print_generic_expr (f, partition_to_var (map, q), TDF_SLIM);
+		  fprintf (f, " - ");
+		}
+	      fprintf (f, "%d ", y);
+	    }
+	}
+      if (t != 0)
+	fprintf (f, ")\n");
+    }
+  fprintf (f, "\n");
+}
+
+/* Given SSA_NAMEs NAME1 and NAME2, return true if they are candidates for
+   coalescing together, false otherwise.
+
+   This must stay consistent with var_map_base_init in tree-ssa-live.c.  */
+
+bool
+gimple_can_coalesce_p (tree name1, tree name2)
+{
+  /* First check the SSA_NAME's associated DECL.  Without
+     optimization, we only want to coalesce if they have the same DECL
+     or both have no associated DECL.  */
+  tree var1 = SSA_NAME_VAR (name1);
+  tree var2 = SSA_NAME_VAR (name2);
+  var1 = (var1 && (!VAR_P (var1) || !DECL_IGNORED_P (var1))) ? var1 : NULL_TREE;
+  var2 = (var2 && (!VAR_P (var2) || !DECL_IGNORED_P (var2))) ? var2 : NULL_TREE;
+  if (var1 != var2 && !flag_tree_coalesce_vars)
+    return false;
+
+  /* Now check the types.  If the types are the same, then we should
+     try to coalesce V1 and V2.  */
+  tree t1 = TREE_TYPE (name1);
+  tree t2 = TREE_TYPE (name2);
+  if (t1 == t2)
+    {
+    check_modes:
+      /* If the base variables are the same, we're good: none of the
+	 other tests below could possibly fail.  */
+      var1 = SSA_NAME_VAR (name1);
+      var2 = SSA_NAME_VAR (name2);
+      if (var1 == var2)
+	return true;
+
+      /* We don't want to coalesce two SSA names if one of the base
+	 variables is supposed to be a register while the other is
+	 supposed to be on the stack.  Anonymous SSA names take
+	 registers, but when not optimizing, user variables should go
+	 on the stack, so coalescing them with the anonymous variable
+	 as the partition leader would end up assigning the user
+	 variable to a register.  Don't do that!  */
+      bool reg1 = !var1 || use_register_for_decl (var1);
+      bool reg2 = !var2 || use_register_for_decl (var2);
+      if (reg1 != reg2)
+	return false;
+
+      /* Check that the promoted modes are the same.  We don't want to
+	 coalesce if the promoted modes would be different.  Only
+	 PARM_DECLs and RESULT_DECLs have different promotion rules,
+	 so skip the test if we both are variables or anonymous
+	 SSA_NAMEs.  */
+      return ((!var1 || VAR_P (var1)) && (!var2 || VAR_P (var2)))
+	|| promote_ssa_mode (name1, NULL) == promote_ssa_mode (name2, NULL);
+    }
+
+  /* If the types are not the same, check for a canonical type match.  This
+     (for example) allows coalescing when the types are fundamentally the
+     same, but just have different names. 
+
+     Note pointer types with different address spaces may have the same
+     canonical type.  Those are rejected for coalescing by the
+     types_compatible_p check.  */
+  if (TYPE_CANONICAL (t1)
+      && TYPE_CANONICAL (t1) == TYPE_CANONICAL (t2)
+      && types_compatible_p (t1, t2))
+    goto check_modes;
+
+  return false;
+}
+
+/* Fill in MAP's partition_to_base_index, with one index for each
+   partition of SSA names USED_IN_COPIES and related by CL coalesce
+   possibilities.  This must match gimple_can_coalesce_p in the
+   optimized case.  */
+
+static void
+compute_optimized_partition_bases (var_map map, bitmap used_in_copies,
+				   coalesce_list_p cl)
+{
+  int parts = num_var_partitions (map);
+  partition tentative = partition_new (parts);
+
+  /* Partition the SSA versions so that, for each coalescible
+     pair, both of its members are in the same partition in
+     TENTATIVE.  */
+  gcc_assert (!cl->sorted);
+  coalesce_pair_p node;
+  coalesce_iterator_type ppi;
+  FOR_EACH_PARTITION_PAIR (node, ppi, cl)
+    {
+      tree v1 = ssa_name (node->first_element);
+      int p1 = partition_find (tentative, var_to_partition (map, v1));
+      tree v2 = ssa_name (node->second_element);
+      int p2 = partition_find (tentative, var_to_partition (map, v2));
+
+      if (p1 == p2)
+	continue;
+
+      partition_union (tentative, p1, p2);
+    }
+
+  /* We have to deal with cost one pairs too.  */
+  for (cost_one_pair_d *co = cl->cost_one_list; co; co = co->next)
+    {
+      tree v1 = ssa_name (co->first_element);
+      int p1 = partition_find (tentative, var_to_partition (map, v1));
+      tree v2 = ssa_name (co->second_element);
+      int p2 = partition_find (tentative, var_to_partition (map, v2));
+
+      if (p1 == p2)
+	continue;
+
+      partition_union (tentative, p1, p2);
+    }
+
+  /* And also with abnormal edges.  */
+  basic_block bb;
+  edge e;
+  edge_iterator ei;
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      FOR_EACH_EDGE (e, ei, bb->preds)
+	if (e->flags & EDGE_ABNORMAL)
+	  {
+	    gphi_iterator gsi;
+	    for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
+		 gsi_next (&gsi))
+	      {
+		gphi *phi = gsi.phi ();
+		tree arg = PHI_ARG_DEF (phi, e->dest_idx);
+		if (SSA_NAME_IS_DEFAULT_DEF (arg)
+		    && (!SSA_NAME_VAR (arg)
+			|| TREE_CODE (SSA_NAME_VAR (arg)) != PARM_DECL))
+		  continue;
+
+		tree res = PHI_RESULT (phi);
+
+		int p1 = partition_find (tentative, var_to_partition (map, res));
+		int p2 = partition_find (tentative, var_to_partition (map, arg));
+
+		if (p1 == p2)
+		  continue;
+
+		partition_union (tentative, p1, p2);
+	      }
+	  }
+    }
+
+  map->partition_to_base_index = XCNEWVEC (int, parts);
+  auto_vec<unsigned int> index_map (parts);
+  if (parts)
+    index_map.quick_grow (parts);
+
+  const unsigned no_part = -1;
+  unsigned count = parts;
+  while (count)
+    index_map[--count] = no_part;
+
+  /* Initialize MAP's mapping from partition to base index, using
+     as base indices an enumeration of the TENTATIVE partitions in
+     which each SSA version ended up, so that we compute conflicts
+     between all SSA versions that ended up in the same potential
+     coalesce partition.  */
+  bitmap_iterator bi;
+  unsigned i;
+  EXECUTE_IF_SET_IN_BITMAP (used_in_copies, 0, i, bi)
+    {
+      int pidx = var_to_partition (map, ssa_name (i));
+      int base = partition_find (tentative, pidx);
+      if (index_map[base] != no_part)
+	continue;
+      index_map[base] = count++;
+    }
+
+  map->num_basevars = count;
+
+  EXECUTE_IF_SET_IN_BITMAP (used_in_copies, 0, i, bi)
+    {
+      int pidx = var_to_partition (map, ssa_name (i));
+      int base = partition_find (tentative, pidx);
+      gcc_assert (index_map[base] < count);
+      map->partition_to_base_index[pidx] = index_map[base];
+    }
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    dump_part_var_map (dump_file, tentative, map);
+
+  partition_delete (tentative);
+}
+
+/* Hashtable helpers.  */
+
+struct tree_int_map_hasher : nofree_ptr_hash <tree_int_map>
+{
+  static inline hashval_t hash (const tree_int_map *);
+  static inline bool equal (const tree_int_map *, const tree_int_map *);
+};
+
+inline hashval_t
+tree_int_map_hasher::hash (const tree_int_map *v)
+{
+  return tree_map_base_hash (v);
+}
+
+inline bool
+tree_int_map_hasher::equal (const tree_int_map *v, const tree_int_map *c)
+{
+  return tree_int_map_eq (v, c);
+}
+
+/* This routine will initialize the basevar fields of MAP with base
+   names.  Partitions will share the same base if they have the same
+   SSA_NAME_VAR, or, being anonymous variables, the same type.  This
+   must match gimple_can_coalesce_p in the non-optimized case.  */
+
+static void
+compute_samebase_partition_bases (var_map map)
+{
+  int x, num_part;
+  tree var;
+  struct tree_int_map *m, *mapstorage;
+
+  num_part = num_var_partitions (map);
+  hash_table<tree_int_map_hasher> tree_to_index (num_part);
+  /* We can have at most num_part entries in the hash tables, so it's
+     enough to allocate so many map elements once, saving some malloc
+     calls.  */
+  mapstorage = m = XNEWVEC (struct tree_int_map, num_part);
+
+  /* If a base table already exists, clear it, otherwise create it.  */
+  free (map->partition_to_base_index);
+  map->partition_to_base_index = (int *) xmalloc (sizeof (int) * num_part);
+
+  /* Build the base variable list, and point partitions at their bases.  */
+  for (x = 0; x < num_part; x++)
+    {
+      struct tree_int_map **slot;
+      unsigned baseindex;
+      var = partition_to_var (map, x);
+      if (SSA_NAME_VAR (var)
+	  && (!VAR_P (SSA_NAME_VAR (var))
+	      || !DECL_IGNORED_P (SSA_NAME_VAR (var))))
+	m->base.from = SSA_NAME_VAR (var);
+      else
+	/* This restricts what anonymous SSA names we can coalesce
+	   as it restricts the sets we compute conflicts for.
+	   Using TREE_TYPE to generate sets is the easies as
+	   type equivalency also holds for SSA names with the same
+	   underlying decl.
+
+	   Check gimple_can_coalesce_p when changing this code.  */
+	m->base.from = (TYPE_CANONICAL (TREE_TYPE (var))
+			? TYPE_CANONICAL (TREE_TYPE (var))
+			: TREE_TYPE (var));
+      /* If base variable hasn't been seen, set it up.  */
+      slot = tree_to_index.find_slot (m, INSERT);
+      if (!*slot)
+	{
+	  baseindex = m - mapstorage;
+	  m->to = baseindex;
+	  *slot = m;
+	  m++;
+	}
+      else
+	baseindex = (*slot)->to;
+      map->partition_to_base_index[x] = baseindex;
+    }
+
+  map->num_basevars = m - mapstorage;
+
+  free (mapstorage);
+}
+
 /* Reduce the number of copies by coalescing variables in the function.  Return
    a partition map with the resulting coalesces.  */
 
@@ -1260,9 +1619,10 @@  coalesce_ssa_name (void)
   cl = create_coalesce_list ();
   map = create_outofssa_var_map (cl, used_in_copies);
 
-  /* If optimization is disabled, we need to coalesce all the names originating
-     from the same SSA_NAME_VAR so debug info remains undisturbed.  */
-  if (!optimize)
+  /* If this optimization is disabled, we need to coalesce all the
+     names originating from the same SSA_NAME_VAR so debug info
+     remains undisturbed.  */
+  if (!flag_tree_coalesce_vars)
     {
       hash_table<ssa_name_var_hash> ssa_name_hash (10);
 
@@ -1303,8 +1663,13 @@  coalesce_ssa_name (void)
   if (dump_file && (dump_flags & TDF_DETAILS))
     dump_var_map (dump_file, map);
 
-  /* Don't calculate live ranges for variables not in the coalesce list.  */
-  partition_view_bitmap (map, used_in_copies, true);
+  partition_view_bitmap (map, used_in_copies);
+
+  if (flag_tree_coalesce_vars)
+    compute_optimized_partition_bases (map, used_in_copies, cl);
+  else
+    compute_samebase_partition_bases (map);
+
   BITMAP_FREE (used_in_copies);
 
   if (num_var_partitions (map) < 1)
@@ -1343,8 +1708,7 @@  coalesce_ssa_name (void)
 
   /* Now coalesce everything in the list.  */
   coalesce_partitions (map, graph, cl,
-		       ((dump_flags & TDF_DETAILS) ? dump_file
-						   : NULL));
+		       ((dump_flags & TDF_DETAILS) ? dump_file : NULL));
 
   delete_coalesce_list (cl);
   ssa_conflicts_delete (graph);
diff --git a/gcc/tree-ssa-coalesce.h b/gcc/tree-ssa-coalesce.h
index 99b188a..ae289b4 100644
--- a/gcc/tree-ssa-coalesce.h
+++ b/gcc/tree-ssa-coalesce.h
@@ -21,5 +21,6 @@  along with GCC; see the file COPYING3.  If not see
 #define GCC_TREE_SSA_COALESCE_H
 
 extern var_map coalesce_ssa_name (void);
+extern bool gimple_can_coalesce_p (tree, tree);
 
 #endif /* GCC_TREE_SSA_COALESCE_H */
diff --git a/gcc/tree-ssa-copyrename.c b/gcc/tree-ssa-copyrename.c
deleted file mode 100644
index aeb7f28..0000000
--- a/gcc/tree-ssa-copyrename.c
+++ /dev/null
@@ -1,475 +0,0 @@ 
-/* Rename SSA copies.
-   Copyright (C) 2004-2015 Free Software Foundation, Inc.
-   Contributed by Andrew MacLeod <amacleod@redhat.com>
-
-This file is part of GCC.
-
-GCC is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 3, or (at your option)
-any later version.
-
-GCC is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING3.  If not see
-<http://www.gnu.org/licenses/>.  */
-
-#include "config.h"
-#include "system.h"
-#include "coretypes.h"
-#include "backend.h"
-#include "tree.h"
-#include "gimple.h"
-#include "rtl.h"
-#include "ssa.h"
-#include "alias.h"
-#include "fold-const.h"
-#include "internal-fn.h"
-#include "gimple-iterator.h"
-#include "flags.h"
-#include "tree-pretty-print.h"
-#include "insn-config.h"
-#include "expmed.h"
-#include "dojump.h"
-#include "explow.h"
-#include "calls.h"
-#include "emit-rtl.h"
-#include "varasm.h"
-#include "stmt.h"
-#include "expr.h"
-#include "tree-dfa.h"
-#include "tree-inline.h"
-#include "tree-ssa-live.h"
-#include "tree-pass.h"
-#include "langhooks.h"
-
-static struct
-{
-  /* Number of copies coalesced.  */
-  int coalesced;
-} stats;
-
-/* The following routines implement the SSA copy renaming phase.
-
-   This optimization looks for copies between 2 SSA_NAMES, either through a
-   direct copy, or an implicit one via a PHI node result and its arguments.
-
-   Each copy is examined to determine if it is possible to rename the base
-   variable of one of the operands to the same variable as the other operand.
-   i.e.
-   T.3_5 = <blah>
-   a_1 = T.3_5
-
-   If this copy couldn't be copy propagated, it could possibly remain in the
-   program throughout the optimization phases.   After SSA->normal, it would
-   become:
-
-   T.3 = <blah>
-   a = T.3
-
-   Since T.3_5 is distinct from all other SSA versions of T.3, there is no
-   fundamental reason why the base variable needs to be T.3, subject to
-   certain restrictions.  This optimization attempts to determine if we can
-   change the base variable on copies like this, and result in code such as:
-
-   a_5 = <blah>
-   a_1 = a_5
-
-   This gives the SSA->normal pass a shot at coalescing a_1 and a_5. If it is
-   possible, the copy goes away completely. If it isn't possible, a new temp
-   will be created for a_5, and you will end up with the exact same code:
-
-   a.8 = <blah>
-   a = a.8
-
-   The other benefit of performing this optimization relates to what variables
-   are chosen in copies.  Gimplification of the program uses temporaries for
-   a lot of things. expressions like
-
-   a_1 = <blah>
-   <blah2> = a_1
-
-   get turned into
-
-   T.3_5 = <blah>
-   a_1 = T.3_5
-   <blah2> = a_1
-
-   Copy propagation is done in a forward direction, and if we can propagate
-   through the copy, we end up with:
-
-   T.3_5 = <blah>
-   <blah2> = T.3_5
-
-   The copy is gone, but so is all reference to the user variable 'a'. By
-   performing this optimization, we would see the sequence:
-
-   a_5 = <blah>
-   a_1 = a_5
-   <blah2> = a_1
-
-   which copy propagation would then turn into:
-
-   a_5 = <blah>
-   <blah2> = a_5
-
-   and so we still retain the user variable whenever possible.  */
-
-
-/* Coalesce the partitions in MAP representing VAR1 and VAR2 if it is valid.
-   Choose a representative for the partition, and send debug info to DEBUG.  */
-
-static void
-copy_rename_partition_coalesce (var_map map, tree var1, tree var2, FILE *debug)
-{
-  int p1, p2, p3;
-  tree root1, root2;
-  tree rep1, rep2;
-  bool ign1, ign2, abnorm;
-
-  gcc_assert (TREE_CODE (var1) == SSA_NAME);
-  gcc_assert (TREE_CODE (var2) == SSA_NAME);
-
-  register_ssa_partition (map, var1);
-  register_ssa_partition (map, var2);
-
-  p1 = partition_find (map->var_partition, SSA_NAME_VERSION (var1));
-  p2 = partition_find (map->var_partition, SSA_NAME_VERSION (var2));
-
-  if (debug)
-    {
-      fprintf (debug, "Try : ");
-      print_generic_expr (debug, var1, TDF_SLIM);
-      fprintf (debug, "(P%d) & ", p1);
-      print_generic_expr (debug, var2, TDF_SLIM);
-      fprintf (debug, "(P%d)", p2);
-    }
-
-  gcc_assert (p1 != NO_PARTITION);
-  gcc_assert (p2 != NO_PARTITION);
-
-  if (p1 == p2)
-    {
-      if (debug)
-	fprintf (debug, " : Already coalesced.\n");
-      return;
-    }
-
-  rep1 = partition_to_var (map, p1);
-  rep2 = partition_to_var (map, p2);
-  root1 = SSA_NAME_VAR (rep1);
-  root2 = SSA_NAME_VAR (rep2);
-  if (!root1 && !root2)
-    return;
-
-  /* Don't coalesce if one of the variables occurs in an abnormal PHI.  */
-  abnorm = (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rep1)
-	    || SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rep2));
-  if (abnorm)
-    {
-      if (debug)
-	fprintf (debug, " : Abnormal PHI barrier.  No coalesce.\n");
-      return;
-    }
-
-  /* Partitions already have the same root, simply merge them.  */
-  if (root1 == root2)
-    {
-      p1 = partition_union (map->var_partition, p1, p2);
-      if (debug)
-	fprintf (debug, " : Same root, coalesced --> P%d.\n", p1);
-      return;
-    }
-
-  /* Never attempt to coalesce 2 different parameters.  */
-  if ((root1 && TREE_CODE (root1) == PARM_DECL)
-      && (root2 && TREE_CODE (root2) == PARM_DECL))
-    {
-      if (debug)
-        fprintf (debug, " : 2 different PARM_DECLS. No coalesce.\n");
-      return;
-    }
-
-  if ((root1 && TREE_CODE (root1) == RESULT_DECL)
-      != (root2 && TREE_CODE (root2) == RESULT_DECL))
-    {
-      if (debug)
-        fprintf (debug, " : One root a RESULT_DECL. No coalesce.\n");
-      return;
-    }
-
-  ign1 = !root1 || (TREE_CODE (root1) == VAR_DECL && DECL_IGNORED_P (root1));
-  ign2 = !root2 || (TREE_CODE (root2) == VAR_DECL && DECL_IGNORED_P (root2));
-
-  /* Refrain from coalescing user variables, if requested.  */
-  if (!ign1 && !ign2)
-    {
-      if (flag_ssa_coalesce_vars && DECL_FROM_INLINE (root2))
-	ign2 = true;
-      else if (flag_ssa_coalesce_vars && DECL_FROM_INLINE (root1))
-	ign1 = true;
-      else if (flag_ssa_coalesce_vars != 2)
-	{
-	  if (debug)
-	    fprintf (debug, " : 2 different USER vars. No coalesce.\n");
-	  return;
-	}
-      else
-	ign2 = true;
-    }
-
-  /* If both values have default defs, we can't coalesce.  If only one has a
-     tag, make sure that variable is the new root partition.  */
-  if (root1 && ssa_default_def (cfun, root1))
-    {
-      if (root2 && ssa_default_def (cfun, root2))
-	{
-	  if (debug)
-	    fprintf (debug, " : 2 default defs. No coalesce.\n");
-	  return;
-	}
-      else
-        {
-	  ign2 = true;
-	  ign1 = false;
-	}
-    }
-  else if (root2 && ssa_default_def (cfun, root2))
-    {
-      ign1 = true;
-      ign2 = false;
-    }
-
-  /* Do not coalesce if we cannot assign a symbol to the partition.  */
-  if (!(!ign2 && root2)
-      && !(!ign1 && root1))
-    {
-      if (debug)
-	fprintf (debug, " : Choosen variable has no root.  No coalesce.\n");
-      return;
-    }
-
-  /* Don't coalesce if the new chosen root variable would be read-only.
-     If both ign1 && ign2, then the root var of the larger partition
-     wins, so reject in that case if any of the root vars is TREE_READONLY.
-     Otherwise reject only if the root var, on which replace_ssa_name_symbol
-     will be called below, is readonly.  */
-  if (((root1 && TREE_READONLY (root1)) && ign2)
-      || ((root2 && TREE_READONLY (root2)) && ign1))
-    {
-      if (debug)
-	fprintf (debug, " : Readonly variable.  No coalesce.\n");
-      return;
-    }
-
-  /* Don't coalesce if the two variables aren't type compatible .  */
-  if (!types_compatible_p (TREE_TYPE (var1), TREE_TYPE (var2))
-      /* There is a disconnect between the middle-end type-system and
-         VRP, avoid coalescing enum types with different bounds.  */
-      || ((TREE_CODE (TREE_TYPE (var1)) == ENUMERAL_TYPE
-	   || TREE_CODE (TREE_TYPE (var2)) == ENUMERAL_TYPE)
-	  && TREE_TYPE (var1) != TREE_TYPE (var2)))
-    {
-      if (debug)
-	fprintf (debug, " : Incompatible types.  No coalesce.\n");
-      return;
-    }
-
-  /* Merge the two partitions.  */
-  p3 = partition_union (map->var_partition, p1, p2);
-
-  /* Set the root variable of the partition to the better choice, if there is
-     one.  */
-  if (!ign2 && root2)
-    replace_ssa_name_symbol (partition_to_var (map, p3), root2);
-  else if (!ign1 && root1)
-    replace_ssa_name_symbol (partition_to_var (map, p3), root1);
-  else
-    gcc_unreachable ();
-
-  if (debug)
-    {
-      fprintf (debug, " --> P%d ", p3);
-      print_generic_expr (debug, SSA_NAME_VAR (partition_to_var (map, p3)),
-			  TDF_SLIM);
-      fprintf (debug, "\n");
-    }
-}
-
-
-namespace {
-
-const pass_data pass_data_rename_ssa_copies =
-{
-  GIMPLE_PASS, /* type */
-  "copyrename", /* name */
-  OPTGROUP_NONE, /* optinfo_flags */
-  TV_TREE_COPY_RENAME, /* tv_id */
-  ( PROP_cfg | PROP_ssa ), /* properties_required */
-  0, /* properties_provided */
-  0, /* properties_destroyed */
-  0, /* todo_flags_start */
-  0, /* todo_flags_finish */
-};
-
-class pass_rename_ssa_copies : public gimple_opt_pass
-{
-public:
-  pass_rename_ssa_copies (gcc::context *ctxt)
-    : gimple_opt_pass (pass_data_rename_ssa_copies, ctxt)
-  {}
-
-  /* opt_pass methods: */
-  opt_pass * clone () { return new pass_rename_ssa_copies (m_ctxt); }
-  virtual bool gate (function *) { return flag_tree_copyrename != 0; }
-  virtual unsigned int execute (function *);
-
-}; // class pass_rename_ssa_copies
-
-/* This function will make a pass through the IL, and attempt to coalesce any
-   SSA versions which occur in PHI's or copies.  Coalescing is accomplished by
-   changing the underlying root variable of all coalesced version.  This will
-   then cause the SSA->normal pass to attempt to coalesce them all to the same
-   variable.  */
-
-unsigned int
-pass_rename_ssa_copies::execute (function *fun)
-{
-  var_map map;
-  basic_block bb;
-  tree var, part_var;
-  gimple stmt;
-  unsigned x;
-  FILE *debug;
-
-  memset (&stats, 0, sizeof (stats));
-
-  if (dump_file && (dump_flags & TDF_DETAILS))
-    debug = dump_file;
-  else
-    debug = NULL;
-
-  map = init_var_map (num_ssa_names);
-
-  FOR_EACH_BB_FN (bb, fun)
-    {
-      /* Scan for real copies.  */
-      for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi);
-	   gsi_next (&gsi))
-	{
-	  stmt = gsi_stmt (gsi);
-	  if (gimple_assign_ssa_name_copy_p (stmt))
-	    {
-	      tree lhs = gimple_assign_lhs (stmt);
-	      tree rhs = gimple_assign_rhs1 (stmt);
-
-	      copy_rename_partition_coalesce (map, lhs, rhs, debug);
-	    }
-	}
-    }
-
-  FOR_EACH_BB_FN (bb, fun)
-    {
-      /* Treat PHI nodes as copies between the result and each argument.  */
-      for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
-	   gsi_next (&gsi))
-        {
-          size_t i;
-	  tree res;
-	  gphi *phi = gsi.phi ();
-	  res = gimple_phi_result (phi);
-
-	  /* Do not process virtual SSA_NAMES.  */
-	  if (virtual_operand_p (res))
-	    continue;
-
-	  /* Make sure to only use the same partition for an argument
-	     as the result but never the other way around.  */
-	  if (SSA_NAME_VAR (res)
-	      && !DECL_IGNORED_P (SSA_NAME_VAR (res)))
-	    for (i = 0; i < gimple_phi_num_args (phi); i++)
-	      {
-		tree arg = PHI_ARG_DEF (phi, i);
-		if (TREE_CODE (arg) == SSA_NAME)
-		  copy_rename_partition_coalesce (map, res, arg,
-						  debug);
-	      }
-	  /* Else if all arguments are in the same partition try to merge
-	     it with the result.  */
-	  else
-	    {
-	      int all_p_same = -1;
-	      int p = -1;
-	      for (i = 0; i < gimple_phi_num_args (phi); i++)
-		{
-		  tree arg = PHI_ARG_DEF (phi, i);
-		  if (TREE_CODE (arg) != SSA_NAME)
-		    {
-		      all_p_same = 0;
-		      break;
-		    }
-		  else if (all_p_same == -1)
-		    {
-		      p = partition_find (map->var_partition,
-					  SSA_NAME_VERSION (arg));
-		      all_p_same = 1;
-		    }
-		  else if (all_p_same == 1
-			   && p != partition_find (map->var_partition,
-						   SSA_NAME_VERSION (arg)))
-		    {
-		      all_p_same = 0;
-		      break;
-		    }
-		}
-	      if (all_p_same == 1)
-		copy_rename_partition_coalesce (map, res,
-						PHI_ARG_DEF (phi, 0),
-						debug);
-	    }
-        }
-    }
-
-  if (debug)
-    dump_var_map (debug, map);
-
-  /* Now one more pass to make all elements of a partition share the same
-     root variable.  */
-
-  for (x = 1; x < num_ssa_names; x++)
-    {
-      part_var = partition_to_var (map, x);
-      if (!part_var)
-        continue;
-      var = ssa_name (x);
-      if (SSA_NAME_VAR (var) == SSA_NAME_VAR (part_var))
-	continue;
-      if (debug)
-        {
-	  fprintf (debug, "Coalesced ");
-	  print_generic_expr (debug, var, TDF_SLIM);
-	  fprintf (debug, " to ");
-	  print_generic_expr (debug, part_var, TDF_SLIM);
-	  fprintf (debug, "\n");
-	}
-      stats.coalesced++;
-      replace_ssa_name_symbol (var, SSA_NAME_VAR (part_var));
-    }
-
-  statistics_counter_event (fun, "copies coalesced",
-			    stats.coalesced);
-  delete_var_map (map);
-  return 0;
-}
-
-} // anon namespace
-
-gimple_opt_pass *
-make_pass_rename_ssa_copies (gcc::context *ctxt)
-{
-  return new pass_rename_ssa_copies (ctxt);
-}
diff --git a/gcc/tree-ssa-live.c b/gcc/tree-ssa-live.c
index 5b00f58..4772558 100644
--- a/gcc/tree-ssa-live.c
+++ b/gcc/tree-ssa-live.c
@@ -70,88 +70,6 @@  static void  verify_live_on_entry (tree_live_info_p);
    ssa_name or variable, and vice versa.  */
 
 
-/* Hashtable helpers.  */
-
-struct tree_int_map_hasher : nofree_ptr_hash <tree_int_map>
-{
-  static inline hashval_t hash (const tree_int_map *);
-  static inline bool equal (const tree_int_map *, const tree_int_map *);
-};
-
-inline hashval_t
-tree_int_map_hasher::hash (const tree_int_map *v)
-{
-  return tree_map_base_hash (v);
-}
-
-inline bool
-tree_int_map_hasher::equal (const tree_int_map *v, const tree_int_map *c)
-{
-  return tree_int_map_eq (v, c);
-}
-
-
-/* This routine will initialize the basevar fields of MAP.  */
-
-static void
-var_map_base_init (var_map map)
-{
-  int x, num_part;
-  tree var;
-  struct tree_int_map *m, *mapstorage;
-
-  num_part = num_var_partitions (map);
-  hash_table<tree_int_map_hasher> tree_to_index (num_part);
-  /* We can have at most num_part entries in the hash tables, so it's
-     enough to allocate so many map elements once, saving some malloc
-     calls.  */
-  mapstorage = m = XNEWVEC (struct tree_int_map, num_part);
-
-  /* If a base table already exists, clear it, otherwise create it.  */
-  free (map->partition_to_base_index);
-  map->partition_to_base_index = (int *) xmalloc (sizeof (int) * num_part);
-
-  /* Build the base variable list, and point partitions at their bases.  */
-  for (x = 0; x < num_part; x++)
-    {
-      struct tree_int_map **slot;
-      unsigned baseindex;
-      var = partition_to_var (map, x);
-      if (SSA_NAME_VAR (var)
-	  && (!VAR_P (SSA_NAME_VAR (var))
-	      || !DECL_IGNORED_P (SSA_NAME_VAR (var))))
-	m->base.from = SSA_NAME_VAR (var);
-      else
-	/* This restricts what anonymous SSA names we can coalesce
-	   as it restricts the sets we compute conflicts for.
-	   Using TREE_TYPE to generate sets is the easies as
-	   type equivalency also holds for SSA names with the same
-	   underlying decl. 
-
-	   Check gimple_can_coalesce_p when changing this code.  */
-	m->base.from = (TYPE_CANONICAL (TREE_TYPE (var))
-			? TYPE_CANONICAL (TREE_TYPE (var))
-			: TREE_TYPE (var));
-      /* If base variable hasn't been seen, set it up.  */
-      slot = tree_to_index.find_slot (m, INSERT);
-      if (!*slot)
-	{
-	  baseindex = m - mapstorage;
-	  m->to = baseindex;
-	  *slot = m;
-	  m++;
-	}
-      else
-	baseindex = (*slot)->to;
-      map->partition_to_base_index[x] = baseindex;
-    }
-
-  map->num_basevars = m - mapstorage;
-
-  free (mapstorage);
-}
-
-
 /* Remove the base table in MAP.  */
 
 static void
@@ -329,21 +247,17 @@  partition_view_fini (var_map map, bitmap selected)
 }
 
 
-/* Create a partition view which includes all the used partitions in MAP.  If
-   WANT_BASES is true, create the base variable map as well.  */
+/* Create a partition view which includes all the used partitions in MAP.  */
 
 void
-partition_view_normal (var_map map, bool want_bases)
+partition_view_normal (var_map map)
 {
   bitmap used;
 
   used = partition_view_init (map);
   partition_view_fini (map, used);
 
-  if (want_bases)
-    var_map_base_init (map);
-  else
-    var_map_base_fini (map);
+  var_map_base_fini (map);
 }
 
 
@@ -352,7 +266,7 @@  partition_view_normal (var_map map, bool want_bases)
    as well.  */
 
 void
-partition_view_bitmap (var_map map, bitmap only, bool want_bases)
+partition_view_bitmap (var_map map, bitmap only)
 {
   bitmap used;
   bitmap new_partitions = BITMAP_ALLOC (NULL);
@@ -368,10 +282,7 @@  partition_view_bitmap (var_map map, bitmap only, bool want_bases)
     }
   partition_view_fini (map, new_partitions);
 
-  if (want_bases)
-    var_map_base_init (map);
-  else
-    var_map_base_fini (map);
+  var_map_base_fini (map);
 }
 
 
diff --git a/gcc/tree-ssa-live.h b/gcc/tree-ssa-live.h
index d5d7820..1f88358 100644
--- a/gcc/tree-ssa-live.h
+++ b/gcc/tree-ssa-live.h
@@ -71,8 +71,8 @@  typedef struct _var_map
 extern var_map init_var_map (int);
 extern void delete_var_map (var_map);
 extern int var_union (var_map, tree, tree);
-extern void partition_view_normal (var_map, bool);
-extern void partition_view_bitmap (var_map, bitmap, bool);
+extern void partition_view_normal (var_map);
+extern void partition_view_bitmap (var_map, bitmap);
 extern void dump_scope_blocks (FILE *, int);
 extern void debug_scope_block (tree, int);
 extern void debug_scope_blocks (int);
diff --git a/gcc/tree-ssa-uncprop.c b/gcc/tree-ssa-uncprop.c
index 437f69d..1fbd71e 100644
--- a/gcc/tree-ssa-uncprop.c
+++ b/gcc/tree-ssa-uncprop.c
@@ -38,6 +38,11 @@  along with GCC; see the file COPYING3.  If not see
 #include "tree-pass.h"
 #include "tree-ssa-propagate.h"
 #include "tree-hash-traits.h"
+#include "bitmap.h"
+#include "stringpool.h"
+#include "tree-ssanames.h"
+#include "tree-ssa-live.h"
+#include "tree-ssa-coalesce.h"
 
 /* The basic structure describing an equivalency created by traversing
    an edge.  Traversing the edge effectively means that we can assume
diff --git a/gcc/var-tracking.c b/gcc/var-tracking.c
index da9de28..a31a137 100644
--- a/gcc/var-tracking.c
+++ b/gcc/var-tracking.c
@@ -4856,12 +4856,16 @@  dataflow_set_remove_mem_locs (variable_def **slot, dataflow_set *set)
    registers, as well as associations between MEMs and VALUEs.  */
 
 static void
-dataflow_set_clear_at_call (dataflow_set *set)
+dataflow_set_clear_at_call (dataflow_set *set, rtx_insn *call_insn)
 {
   unsigned int r;
   hard_reg_set_iterator hrsi;
+  HARD_REG_SET invalidated_regs;
 
-  EXECUTE_IF_SET_IN_HARD_REG_SET (regs_invalidated_by_call, 0, r, hrsi)
+  get_call_reg_set_usage (call_insn, &invalidated_regs,
+			  regs_invalidated_by_call);
+
+  EXECUTE_IF_SET_IN_HARD_REG_SET (invalidated_regs, 0, r, hrsi)
     var_regno_delete (set, r);
 
   if (MAY_HAVE_DEBUG_INSNS)
@@ -6645,7 +6649,7 @@  compute_bb_dataflow (basic_block bb)
       switch (mo->type)
 	{
 	  case MO_CALL:
-	    dataflow_set_clear_at_call (out);
+	    dataflow_set_clear_at_call (out, insn);
 	    break;
 
 	  case MO_USE:
@@ -9107,7 +9111,7 @@  emit_notes_in_bb (basic_block bb, dataflow_set *set)
       switch (mo->type)
 	{
 	  case MO_CALL:
-	    dataflow_set_clear_at_call (set);
+	    dataflow_set_clear_at_call (set, insn);
 	    emit_notes_for_changes (insn, EMIT_NOTE_AFTER_CALL_INSN, set->vars);
 	    {
 	      rtx arguments = mo->u.loc, *p = &arguments;


Adjusted incremental patch:

---
 gcc/function.c    |   39 +++++++++++++++++++++++++++++++++++++--
 gcc/stor-layout.c |    3 ++-
 2 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/gcc/function.c b/gcc/function.c
index 753d889..c3d00cd 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -151,6 +151,8 @@  static bool contains (const_rtx, hash_table<insn_cache_hasher> *);
 static void prepare_function_start (void);
 static void do_clobber_return_reg (rtx, void *);
 static void do_use_return_reg (rtx, void *);
+static rtx rtl_for_parm (struct assign_parm_data_all *, tree);
+
 
 /* Stack of nested functions.  */
 /* Keep track of the cfun stack.  */
@@ -2267,7 +2269,7 @@  assign_parms_initialize_all (struct assign_parm_data_all *all)
    needed, else the old list.  */
 
 static void
-split_complex_args (vec<tree> *args)
+split_complex_args (struct assign_parm_data_all *all, vec<tree> *args)
 {
   unsigned i;
   tree p;
@@ -2278,6 +2280,7 @@  split_complex_args (vec<tree> *args)
       if (TREE_CODE (type) == COMPLEX_TYPE
 	  && targetm.calls.split_complex_arg (type))
 	{
+	  tree cparm = p;
 	  tree decl;
 	  tree subtype = TREE_TYPE (type);
 	  bool addressable = TREE_ADDRESSABLE (p);
@@ -2296,6 +2299,9 @@  split_complex_args (vec<tree> *args)
 	  DECL_ARTIFICIAL (p) = addressable;
 	  DECL_IGNORED_P (p) = addressable;
 	  TREE_ADDRESSABLE (p) = 0;
+	  /* Reset the RTL before layout_decl, or it may change the
+	     mode of the RTL of the original argument copied to P.  */
+	  SET_DECL_RTL (p, NULL_RTX);
 	  layout_decl (p, 0);
 	  (*args)[i] = p;
 
@@ -2307,6 +2313,25 @@  split_complex_args (vec<tree> *args)
 	  DECL_IGNORED_P (decl) = addressable;
 	  layout_decl (decl, 0);
 	  args->safe_insert (++i, decl);
+
+	  /* If we are expanding a function, rather than gimplifying
+	     it, propagate the RTL of the complex parm to the split
+	     declarations, and set their contexts so that
+	     maybe_reset_rtl_for_parm can recognize them and refrain
+	     from resetting their RTL.  */
+	  if (currently_expanding_to_rtl)
+	    {
+	      rtx rtl = rtl_for_parm (all, cparm);
+	      gcc_assert (!rtl || GET_CODE (rtl) == CONCAT);
+	      if (rtl)
+		{
+		  SET_DECL_RTL (p, XEXP (rtl, 0));
+		  SET_DECL_RTL (decl, XEXP (rtl, 1));
+
+		  DECL_CONTEXT (p) = cparm;
+		  DECL_CONTEXT (decl) = cparm;
+		}
+	    }
 	}
     }
 }
@@ -2369,7 +2394,7 @@  assign_parms_augmented_arg_list (struct assign_parm_data_all *all)
 
   /* If the target wants to split complex arguments into scalars, do so.  */
   if (targetm.calls.split_complex_arg)
-    split_complex_args (&fnargs);
+    split_complex_args (all, &fnargs);
 
   return fnargs;
 }
@@ -2823,6 +2848,16 @@  maybe_reset_rtl_for_parm (tree parm)
 {
   gcc_assert (TREE_CODE (parm) == PARM_DECL
 	      || TREE_CODE (parm) == RESULT_DECL);
+
+  /* This is a split complex parameter, and its context was set to its
+     original PARM_DECL in split_complex_args so that we could
+     recognize it here and not reset its RTL.  */
+  if (DECL_CONTEXT (parm) && TREE_CODE (DECL_CONTEXT (parm)) == PARM_DECL)
+    {
+      DECL_CONTEXT (parm) = DECL_CONTEXT (DECL_CONTEXT (parm));
+      return;
+    }
+
   if ((flag_tree_coalesce_vars
        || (DECL_RTL_SET_P (parm) && DECL_RTL (parm) == pc_rtx))
       && is_gimple_reg (parm))
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 0d4f4a4..288227a 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -794,7 +794,8 @@  layout_decl (tree decl, unsigned int known_align)
     {
       PUT_MODE (rtl, DECL_MODE (decl));
       SET_DECL_RTL (decl, 0);
-      set_mem_attributes (rtl, decl, 1);
+      if (MEM_P (rtl))
+	set_mem_attributes (rtl, decl, 1);
       SET_DECL_RTL (decl, rtl);
     }
 }