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--- trunk/gcc/tree-ssa-threadedge.c 2014/04/23 17:53:56 209715
+++ trunk/gcc/tree-ssa-threadedge.c 2014/04/23 18:04:46 209716
@@ -387,7 +387,34 @@
&& (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
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