diff mbox

Don't reapply loops flags if unnecessary in loop_optimizer_init

Message ID 5652F743.4020807@mentor.com
State New
Headers show

Commit Message

Tom de Vries Nov. 23, 2015, 11:23 a.m. UTC 
On 23/11/15 11:29, Richard Biener wrote:
> On Mon, 23 Nov 2015, Tom de Vries wrote:
>
>> [ was: Re: [PATCH, 10/16] Add pass_oacc_kernels pass group in passes.def ]
>>
>> On 20/11/15 11:37, Richard Biener wrote:
>>> I'd rather make loop_optimizer_init do nothing
>>> if requested flags are already set and no fixup is needed and
>>> call the above unconditionally.  Thus sth like
>>>
>>> Index: gcc/loop-init.c
>>> ===================================================================
>>> --- gcc/loop-init.c     (revision 230649)
>>> +++ gcc/loop-init.c     (working copy)
>>> @@ -103,7 +103,11 @@ loop_optimizer_init (unsigned flags)
>>>          calculate_dominance_info (CDI_DOMINATORS);
>>>
>>>          if (!needs_fixup)
>>> -       checking_verify_loop_structure ();
>>> +       {
>>> +         checking_verify_loop_structure ();
>>> +         if (loops_state_satisfies_p (flags))
>>> +           goto out;
>>> +       }
>>>
>>>          /* Clear all flags.  */
>>>          if (recorded_exits)
>>> @@ -122,11 +126,12 @@ loop_optimizer_init (unsigned flags)
>>>      /* Apply flags to loops.  */
>>>      apply_loop_flags (flags);
>>>
>>> +  checking_verify_loop_structure ();
>>> +
>>> +out:
>>>      /* Dump loops.  */
>>>      flow_loops_dump (dump_file, NULL, 1);
>>>
>>> -  checking_verify_loop_structure ();
>>> -
>>>      timevar_pop (TV_LOOP_INIT);
>>>    }
>>
>> This patch implements that approach, but the patch is slightly more
>> complicated because of the need to handle LOOPS_MAY_HAVE_MULTIPLE_LATCHES
>> differently than the rest of the flags.
>>
>> Bootstrapped and reg-tested on x86_64.
>>
>> OK for stage3 trunk?
>
> Let's revisit this during stage1 if the scev_initialized () thing
> SLP vectorization uses works, ok?
>

OK, I'll give that a try.

FTR, attached two patches are an attempt at a cleaner solution for 
pass_slp_vectorize::execute (in combination with patch "Don't reapply 
loops flags if unnecessary in loop_optimizer_init").

The first patch introduces a property PROP_scev, set for the duration of 
the loop pipeline. It allows us to call scev_initialize and 
scev_finalize unconditionally. Outside the loop pipeline calling the 
functions has the usual effect. Inside the loop pipeline, calling the 
functions has no effect.

The second patch introduces a property PROP_loops_normal_re_lcssa, set 
for the duration of the loop pipeline. It allows us (in combination with 
"Don't reapply loops flags if unnecessary in loop_optimizer_init") to 
call loop_optimizer_init and loop_optimizer_finalize unconditionally.
Outside the loop pipeline, calling the functions has the usual effect. 
Inside the loop pipeline, calling loop_optimizer_finalize has no effect, 
and calling loop_optimizer_initialize has no effect unless a fixup or a 
new loop property is needed.

Thanks,
- Tom
diff mbox

Patch

Add PROP_loops_normal_re_lcssa

---
 gcc/loop-init.c       | 13 +++++++++++++
 gcc/tree-pass.h       |  3 +++
 gcc/tree-ssa-loop.c   |  4 ++--
 gcc/tree-vectorizer.c | 11 ++---------
 4 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/gcc/loop-init.c b/gcc/loop-init.c
index 4b72cab..9ce3e9e 100644
--- a/gcc/loop-init.c
+++ b/gcc/loop-init.c
@@ -100,6 +100,10 @@  loop_optimizer_init (unsigned flags)
       bool needs_fixup = loops_state_satisfies_p (LOOPS_NEED_FIXUP);
 
       gcc_assert (cfun->curr_properties & PROP_loops);
+      if (cfun->curr_properties & PROP_loops_normal_re_lcssa)
+	gcc_assert (loops_state_satisfies_p (LOOPS_NORMAL
+					     | LOOPS_HAVE_RECORDED_EXITS
+					     | LOOP_CLOSED_SSA));
 
       /* Ensure that the dominators are computed, like flow_loops_find does.  */
       calculate_dominance_info (CDI_DOMINATORS);
@@ -151,6 +155,15 @@  loop_optimizer_finalize (struct function *fn)
   struct loop *loop;
   basic_block bb;
 
+  if (fn->curr_properties & PROP_loops_normal_re_lcssa)
+    {
+      gcc_assert (loops_state_satisfies_p (fn, LOOPS_NORMAL
+					   | LOOPS_HAVE_RECORDED_EXITS
+					   | LOOP_CLOSED_SSA));
+      gcc_assert (!loops_state_satisfies_p (fn, LOOPS_NEED_FIXUP));
+      return;
+    }
+
   timevar_push (TV_LOOP_FINI);
 
   if (loops_state_satisfies_p (fn, LOOPS_HAVE_RECORDED_EXITS))
diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h
index 4e66b2c..c43a5f3 100644
--- a/gcc/tree-pass.h
+++ b/gcc/tree-pass.h
@@ -228,6 +228,9 @@  protected:
 						   current choices have
 						   been optimized.  */
 #define PROP_scev		(1 << 16)	/* preserve scev info.  */
+/* preserve loop structures in LOOPS_NORMAL with recorded exits, and in loop
+   closed ssa.  */
+#define PROP_loops_normal_re_lcssa	(1 << 17)
 
 #define PROP_trees \
   (PROP_gimple_any | PROP_gimple_lcf | PROP_gimple_leh | PROP_gimple_lomp)
diff --git a/gcc/tree-ssa-loop.c b/gcc/tree-ssa-loop.c
index 739fda7..73fbb43 100644
--- a/gcc/tree-ssa-loop.c
+++ b/gcc/tree-ssa-loop.c
@@ -290,7 +290,7 @@  const pass_data pass_data_tree_loop_init =
   OPTGROUP_LOOP, /* optinfo_flags */
   TV_NONE, /* tv_id */
   PROP_cfg, /* properties_required */
-  PROP_scev, /* properties_provided */
+  PROP_loops_normal_re_lcssa | PROP_scev, /* properties_provided */
   0, /* properties_destroyed */
   0, /* todo_flags_start */
   0, /* todo_flags_finish */
@@ -524,7 +524,7 @@  make_pass_iv_optimize (gcc::context *ctxt)
 static unsigned int
 tree_ssa_loop_done (void)
 {
-  cfun->curr_properties &= ~PROP_scev;
+  cfun->curr_properties &= ~(PROP_loops_normal_re_lcssa | PROP_scev);
   free_numbers_of_iterations_estimates (cfun);
   scev_finalize ();
   loop_optimizer_finalize ();
diff --git a/gcc/tree-vectorizer.c b/gcc/tree-vectorizer.c
index b06433d..503f227 100644
--- a/gcc/tree-vectorizer.c
+++ b/gcc/tree-vectorizer.c
@@ -727,11 +727,7 @@  pass_slp_vectorize::execute (function *fun)
 {
   basic_block bb;
 
-  bool in_loop_pipeline = scev_initialized_p ();
-  if (!in_loop_pipeline)
-    {
-      loop_optimizer_init (LOOPS_NORMAL);
-    }
+  loop_optimizer_init (LOOPS_NORMAL);
   scev_initialize ();
 
   /* Mark all stmts as not belonging to the current region and unvisited.  */
@@ -758,10 +754,7 @@  pass_slp_vectorize::execute (function *fun)
   free_stmt_vec_info_vec ();
 
   scev_finalize ();
-  if (!in_loop_pipeline)
-    {
-      loop_optimizer_finalize ();
-    }
+  loop_optimizer_finalize ();
 
   return 0;
 }