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re PR tree-optimization/26213 (new (within last few days) infinite loop with -O1)

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PR tree-optimization/26213
	* tree-ssa-threadedge.c (simplify_control_stmt_condition): Do not
	loop trying to follow SSA_NAME_VALUE chains.

	* gcc.c-torture/compile/pr26213.c: New test.

From-SVN: r110846
This commit is contained in:
Jeff Law 2006-02-10 12:22:58 -07:00 committed by Jeff Law
parent def6613406
commit 61864771af
4 changed files with 33 additions and 4 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2006-02-10 Jeff Law <law@redhat.com>
PR tree-optimization/26213
* tree-ssa-threadedge.c (simplify_control_stmt_condition): Do not
loop trying to follow SSA_NAME_VALUE chains.
2006-02-10 Richard Guenther <rguenther@suse.de>
* tree-dfa.c (get_ref_base_and_extent): When computing maxsize

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2006-02-10 Jeff Law <law@redhat.com>
* gcc.c-torture/compile/pr26213.c: New test.
2006-02-10 Steven G. Kargl <kargls@comcast.net>
gfortran.dg/null_1.f90: New test.

15
gcc/testsuite/gcc.c-torture/compile/pr26213.c Normal file
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@ -0,0 +1,15 @@
void
xnanosleep (_Bool overflow)
{
struct { int tv_nsec; } ts_sleep;
if (0 <= ts_sleep.tv_nsec)
overflow |= 1;
for (;;)
{
if (overflow)
ts_sleep.tv_nsec = 0;
if (foo (ts_sleep))
break;
}
}

12
gcc/tree-ssa-threadedge.c
View File

@ -441,10 +441,14 @@ simplify_control_stmt_condition (edge e,
{
cached_lhs = cond;
/* Get the variable's current value from the equivalency chains. */
while (cached_lhs
&& TREE_CODE (cached_lhs) == SSA_NAME
&& SSA_NAME_VALUE (cached_lhs))
/* Get the variable's current value from the equivalency chains.
It is possible to get loops in the SSA_NAME_VALUE chains
(consider threading the backedge of a loop where we have
a loop invariant SSA_NAME used in the condition. */
if (cached_lhs
&& TREE_CODE (cached_lhs) == SSA_NAME
&& SSA_NAME_VALUE (cached_lhs))
cached_lhs = SSA_NAME_VALUE (cached_lhs);
/* If we're dominated by a suitable ASSERT_EXPR, then