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Don't tail-merge blocks from different loops 

2017-07-03  Tom de Vries  <tom@codesourcery.com>

	PR tree-optimization/81192
	* tree-ssa-tail-merge.c (same_succ_hash): Use bb->loop_father->num in
	hash.
	(same_succ::equal): Don't find bbs to be equal if bb->loop_father
	differs.
	(find_same_succ_bb): Remove obsolete test on bb->loop_father->latch.

	* gcc.dg/pr81192.c: Update.

From-SVN: r249894
This commit is contained in:
Tom de Vries 2017-07-03 07:21:34 +00:00 committed by Tom de Vries
parent 0bbfd5540d
commit 4752be4637
4 changed files with 21 additions and 10 deletions
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9
gcc/ChangeLog
View File

@ -1,3 +1,12 @@
2017-07-03 Tom de Vries <tom@codesourcery.com>
PR tree-optimization/81192
* tree-ssa-tail-merge.c (same_succ_hash): Use bb->loop_father->num in
hash.
(same_succ::equal): Don't find bbs to be equal if bb->loop_father
differs.
(find_same_succ_bb): Remove obsolete test on bb->loop_father->latch.
2017-07-03 Tom de Vries <tom@codesourcery.com>
PR tree-optimization/81192

5
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,8 @@
2017-07-03 Tom de Vries <tom@codesourcery.com>
PR tree-optimization/81192
* gcc.dg/pr81192.c: Update.
2017-07-03 Tom de Vries <tom@codesourcery.com>
PR tree-optimization/81192

2
gcc/testsuite/gcc.dg/pr81192.c
View File

@ -19,4 +19,4 @@ fn2 (void)
;
}
/* { dg-final { scan-tree-dump-times "(?n)find_duplicates: <bb .*> duplicate of <bb .*>" 1 "pre" } } */
/* { dg-final { scan-tree-dump-not "(?n)find_duplicates: <bb .*> duplicate of <bb .*>" "pre" } } */

15
gcc/tree-ssa-tail-merge.c
View File

@ -479,6 +479,8 @@ same_succ_hash (const same_succ *e)
hstate.add_int (size);
BB_SIZE (bb) = size;
hstate.add_int (bb->loop_father->num);
for (i = 0; i < e->succ_flags.length (); ++i)
{
flags = e->succ_flags[i];
@ -568,6 +570,9 @@ same_succ::equal (const same_succ *e1, const same_succ *e2)
if (BB_SIZE (bb1) != BB_SIZE (bb2))
return 0;
if (bb1->loop_father != bb2->loop_father)
return 0;
gsi1 = gsi_start_nondebug_bb (bb1);
gsi2 = gsi_start_nondebug_bb (bb2);
gsi_advance_fw_nondebug_nonlocal (&gsi1);
@ -695,15 +700,7 @@ find_same_succ_bb (basic_block bb, same_succ **same_p)
edge_iterator ei;
edge e;
if (bb == NULL
/* Be conservative with loop structure. It's not evident that this test
is sufficient. Before tail-merge, we've just called
loop_optimizer_finalize, and LOOPS_MAY_HAVE_MULTIPLE_LATCHES is now
set, so there's no guarantee that the loop->latch value is still valid.
But we assume that, since we've forced LOOPS_HAVE_SIMPLE_LATCHES at the
start of pre, we've kept that property intact throughout pre, and are
keeping it throughout tail-merge using this test. */
|| bb->loop_father->latch == bb)
if (bb == NULL)
return;
bitmap_set_bit (same->bbs, bb->index);
FOR_EACH_EDGE (e, ei, bb->succs)