| Message ID | or62uxhtrp.fsf@livre.localdomain |
|---|---|
| State | New |
| Headers | show |
On Tue, Dec 14, 2010 at 5:18 AM, Alexandre Oliva <aoliva@redhat.com> wrote: > On Dec 8, 2010, Richard Guenther <richard.guenther@gmail.com> wrote: > >> On Wed, Dec 8, 2010 at 5:06 AM, Alexandre Oliva <aoliva@redhat.com> wrote: >>> At -O0, we merge blocks or not depending on locus information present at >>> the last insn in a block and the entry locus of the subsequent block. >>> We shouldn't use the locus of a debug insn for this compare, lest we may >>> end up not merging blocks that, with -g0, we would. >>> >>> This seldom occurs in practice, since this patch is only active at -O0, >>> and -fvar-tracking is disabled by default at -O0, even if -g is enabled. >>> However, since it's possible to explicitly activate -fvar-tracking (and >>> -fvar-tracking-assignments), even at -O0, we shouldn't generate >>> different executable code if the user does this. >>> >>> The patch below was regstrapped on x86_64-linux-gnu. Ok to install? > >> Ok. > > A few tweaks were needed for 4.5. Regstrapped on x86_64-linux-gnu, > along with the patch for PR 46576 (unchanged). I'll apply both in the > 4.5 branch if there aren't objections within 20 hours or so, so that the > bug reports can be closed. Please wait until after 4.5.2 is released, the branch is currently frozen. Thanks, Richard. > > > -- > 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 > >
for gcc/ChangeLog from Alexandre Oliva <aoliva@redhat.com> PR debug/46782 * cfgcleanup.c (try_forward_edges): Skip debug insns. for gcc/testsuite/ChangeLog from Alexandre Oliva <aoliva@redhat.com> PR debug/46782 * gcc.dg/debug/pr46782.c: New. Index: gcc/cfgcleanup.c =================================================================== --- gcc/cfgcleanup.c.orig 2010-06-10 13:56:42.000000000 -0300 +++ gcc/cfgcleanup.c 2010-12-13 01:24:08.015744331 -0200 @@ -482,15 +482,20 @@ try_forward_edges (int mode, basic_block /* When not optimizing, ensure that edges or forwarder blocks with different locus are not optimized out. */ int locus = single_succ_edge (target)->goto_locus; + rtx last ; if (locus && goto_locus && !locator_eq (locus, goto_locus)) counter = n_basic_blocks; else if (locus) goto_locus = locus; - if (INSN_P (BB_END (target))) + last = BB_END (target); + if (DEBUG_INSN_P (last)) + last = prev_nondebug_insn (last); + + if (last && INSN_P (last)) { - locus = INSN_LOCATOR (BB_END (target)); + locus = INSN_LOCATOR (last); if (locus && goto_locus && !locator_eq (locus, goto_locus)) Index: gcc/testsuite/gcc.dg/debug/pr46782.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ gcc/testsuite/gcc.dg/debug/pr46782.c 2010-12-13 01:21:44.334901591 -0200 @@ -0,0 +1,11 @@ +/* PR debug/46782 */ +/* { dg-do compile } */ +/* { dg-options "-w -O0 -fvar-tracking -fcompare-debug" } */ + +void foo (int i) +{ + if (i) + i++; + while (i) + ; +}