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re PR rtl-optimization/24899 (loop.c miscompiles libgnomecanvas)

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PR rtl-optimization/24899
	* loop.c (strength_reduce): Don't reduce giv that is not always
	computable and where add_val or mult_val can trap.

	* gcc.c-torture/execute/20051215-1.c: New test.

From-SVN: r108642
This commit is contained in:
Jakub Jelinek 2005-12-16 13:12:41 +01:00 • committed by Jakub Jelinek
parent 0c8c236b7a
commit a1615718f5
4 changed files with 48 additions and 0 deletions
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4
gcc/ChangeLog
View file

@ -1,5 +1,9 @@
2005-12-16 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/24899
* loop.c (strength_reduce): Don't reduce giv that is not always
computable and where add_val or mult_val can trap.
* doc/invoke.texi (-fdump-tree-*): Remove note about C/C++ only.
2005-12-16 Nathan Sidwell <nathan@codesourcery.com>

11
gcc/loop.c
View file

@ -6486,6 +6486,17 @@ strength_reduce (struct loop *loop, int flags)
v->ignore = 1;
bl->all_reduced = 0;
}
else if (!v->always_computable
&& (may_trap_or_fault_p (v->add_val)
|| may_trap_or_fault_p (v->mult_val)))
{
if (loop_dump_stream)
fprintf (loop_dump_stream,
"giv of insn %d: not always computable.\n",
INSN_UID (v->insn));
v->ignore = 1;
bl->all_reduced = 0;
}
else
{
/* Check that we can increment the reduced giv without a

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2005-12-16 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/24899
* gcc.c-torture/execute/20051215-1.c: New test.
2005-12-16 Andreas Krebbel <krebbel1@de.ibm.com>
PR 24823

28
gcc/testsuite/gcc.c-torture/execute/20051215-1.c Normal file
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@ -0,0 +1,28 @@
/* PR rtl-optimization/24899 */
extern void abort (void);
__attribute__ ((noinline)) int
foo (int x, int y, int *z)
{
int a, b, c, d;
a = b = 0;
for (d = 0; d < y; d++)
{
if (z)
b = d * *z;
for (c = 0; c < x; c++)
a += b;
}
return a;
}
int
main (void)
{
if (foo (3, 2, 0) != 0)
abort ();
return 0;
}