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# DP: Fix PR tree-optimization/60902, taken from the trunk.
gcc/
2014-04-28 Jeff Law <law@redhat.com>
PR tree-optimization/60902
* tree-ssa-threadedge.c
(record_temporary_equivalences_from_stmts_at_dest): Only iterate
over real defs when invalidating outputs from statements that do not
produce useful outputs for threading.
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.
gcc/testsuite/
2014-04-23 Jeff Law <law@redhat.com>
PR tree-optimization/60902
* gcc.target/i386/pr60902.c: New test.
--- a/src/gcc/testsuite/gcc.target/i386/pr60902.c
+++ b/src/gcc/testsuite/gcc.target/i386/pr60902.c
@@ -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);
+}
--- a/src/gcc/tree-ssa-threadedge.c
+++ b/src/gcc/tree-ssa-threadedge.c
@@ -387,8 +387,35 @@
&& (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_DEF)
+ {
+ /* 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
results. For example
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