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re PR tree-optimization/60902 (ffmpeg built with gcc 4.9 RC produces incorrect flac playback code)

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PR tree-optimization/60902
	* tree-ssa-threadedge.c
	(record_temporary_equivalences_from_stmts_at_dest): Make sure to
	invalidate outputs from statements that do not produce useful
	outputs for threading.

	PR tree-optimization/60902
	* gcc.target/i386/pr60902.c: New test.

From-SVN: r209716
This commit is contained in:
Jeff Law 2014-04-23 12:04:46 -06:00 committed by Jeff Law
parent 0e4d63c5ee
commit 9219922e54
4 changed files with 73 additions and 1 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2014-04-23 Jeff Law <law@redhat.com>
PR tree-optimization/60902
* tree-ssa-threadedge.c
(record_temporary_equivalences_from_stmts_at_dest): Make sure to
invalidate outputs from statements that do not produce useful
outputs for threading.
2014-04-23 Venkataramanan Kumar <venkataramanan.kumar@linaro.org>
* config/aarch64/aarch64.md (stack_protect_set, stack_protect_test)

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2014-04-23 Jeff Law <law@redhat.com>
PR tree-optimization/60902
* gcc.target/i386/pr60902.c: New test.
2014-04-23 Alex Velenko <Alex.Velenko@arm.com>
* gcc.target/aarch64/vdup_lane_1.c: New testcase.

32
gcc/testsuite/gcc.target/i386/pr60902.c Normal file
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@ -0,0 +1,32 @@
/* { dg-do run } */
/* { dg-options "-O2" } */
extern void abort ();
extern void exit (int);
int x;
foo()
{
static int count;
count++;
if (count > 1)
abort ();
}
static inline int
frob ()
{
int a;
__asm__ ("mov %1, %0\n\t" : "=r" (a) : "m" (x));
x++;
return a;
}
int
main ()
{
int i;
for (i = 0; i < 10 && frob () == 0; i++)
foo();
exit (0);
}

29
gcc/tree-ssa-threadedge.c
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@ -387,7 +387,34 @@ record_temporary_equivalences_from_stmts_at_dest (edge e,
&& (gimple_code (stmt) != GIMPLE_CALL
|| gimple_call_lhs (stmt) == NULL_TREE
|| TREE_CODE (gimple_call_lhs (stmt)) != SSA_NAME))
continue;
{
/* STMT might still have DEFS and we need to invalidate any known
equivalences for them.
Consider if STMT is a GIMPLE_ASM with one or more outputs that
feeds a conditional inside a loop. We might derive an equivalence
due to the conditional. */
tree op;
ssa_op_iter iter;
if (backedge_seen)
FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_ALL_DEFS)
{
/* This call only invalidates equivalences created by
PHI nodes. This is by design to keep the cost of
of invalidation reasonable. */
invalidate_equivalences (op, stack, src_map, dst_map);
/* However, conditionals can imply values for real
operands as well. And those won't be recorded in the
maps. In fact, those equivalences may be recorded totally
outside the threading code. We can just create a new
temporary NULL equivalence here. */
record_temporary_equivalence (op, NULL_TREE, stack);
}
continue;
}
/* The result of __builtin_object_size depends on all the arguments
of a phi node. Temporarily using only one edge produces invalid