| Message ID | orhbdxwsnr.fsf@livre.localdomain |
|---|---|
| State | New |
| Headers | show |
On Tue, Dec 28, 2010 at 9:26 PM, Alexandre Oliva <aoliva@redhat.com> wrote: > On Dec 26, 2010, Richard Guenther <richard.guenther@gmail.com> wrote: > >> Yeah. But wasn't there a correctness problem with propagating as well? > >> the the debug info will refer to the wrong value of i. Remember that >> we can have overlapping life ranges for SSA names but not for the >> decls for which we emit debug info. > > The value expressions in debug stmts refer to the SSA names, so there's > no problem, at least in this regard. The overlapping ranges, if > expanded to different pseudos, it will get the correct RTL expressions; > if no longer available at a point, it should not get any RTL expression > (although it would in theory be possible to do better, looking for some > equivalence). > > Now, I don't think the latter has been actually verified, especially > after the change that made us go straight from SSA to RTL, so if you > have evidence that we're doing it wrong, I'd love to see it. I don't have evidence, it's just what I seem to remember (for some reason). Btw, we can have memory operands on the RHS of debug stmts? For those propagating wouldn't be valid as they are not in SSA form. Richard. >>> Regstrapping your proposed patch now. > >> It's ok to commit if it works (with your testcase). > > Here's what I installed. > > > > -- > Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/ > You must be the change you wish to see in the world. -- Gandhi > Be Free! -- http://FSFLA.org/ FSF Latin America board member > Free Software Evangelist Red Hat Brazil Compiler Engineer > >
On Dec 28, 2010, Richard Guenther <richard.guenther@gmail.com> wrote: > we can have memory operands on the RHS of debug stmts? For those > propagating wouldn't be valid as they are not in SSA form. Yup, the code I posted wouldn't propagate MEMs.
for gcc/ChangeLog from Richard Guenther <rguenther@suse.de> PR debug/46931 * tree-vect-loop-manip.c (slpeel_tree_peel_loop_to_edge): Update SSA before removing dead stmts. Index: gcc/tree-vect-loop-manip.c =================================================================== --- gcc/tree-vect-loop-manip.c.orig 2010-12-18 04:28:14.000000000 -0200 +++ gcc/tree-vect-loop-manip.c 2010-12-23 05:50:15.540018010 -0200 @@ -1442,6 +1442,9 @@ slpeel_tree_peel_loop_to_edge (struct lo if (update_first_loop_count) slpeel_make_loop_iterate_ntimes (first_loop, first_niters); + BITMAP_FREE (definitions); + delete_update_ssa (); + /* Remove all pattern statements from the loop copy. They will confuse the expander if DCE is disabled. ??? The pattern recognizer should be split into an analysis and @@ -1451,9 +1454,6 @@ slpeel_tree_peel_loop_to_edge (struct lo adjust_vec_debug_stmts (); - BITMAP_FREE (definitions); - delete_update_ssa (); - return new_loop; }