re PR tree-optimization/43655 (-ftree-ter causes FAIL:…

re PR tree-optimization/43655 (-ftree-ter causes FAIL: g++.old-deja/g++.law/temps5.C execution test)

	PR tree-optimization/43655
	* tree-ssa-ter.c (is_replaceable_p): Don't use
	gimple_references_memory_p for -O0, instead check for load
	by looking at rhs.

	* g++.dg/opt/pr43655.C: New test.

From-SVN: r167955

gcc/ChangeLog

+2010-12-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/43655
+	* tree-ssa-ter.c (is_replaceable_p): Don't use
+	gimple_references_memory_p for -O0, instead check for load
+	by looking at rhs.
+
 2010-12-16  Sebastian Pop  <sebastian.pop@amd.com>
 
 	PR tree-optimization/46404

gcc/testsuite/ChangeLog

+2010-12-16  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/43655
+	* g++.dg/opt/pr43655.C: New test.
+
 2010-12-16  Sebastian Pop  <sebastian.pop@amd.com>
 
 	PR tree-optimization/46404

gcc/testsuite/g++.dg/opt/pr43655.C

+// PR tree-optimization/43655
+// { dg-do run }
+// { dg-options "-O0 -ftree-ter" }
+
+extern "C" void abort ();
+
+struct C
+{
+  C (int i) : val(i) { }
+  C (const C& c) : val(c.val) { }
+  ~C (void) { val = 999; }
+  C& operator = (const C& c) { val = c.val; return *this; }
+  C& inc (int i) { val += i; return *this; }
+  int val;
+};
+
+C
+f ()
+{
+  return C (3);
+}
+
+C
+f (int i)
+{
+  return f ().inc (i);
+}
+
+int
+main ()
+{
+  if (f (2).val != 5)
+    abort ();
+}

gcc/tree-ssa-ter.c

@@ -416,7 +416,9 @@ is_replaceable_p (gimple stmt)
     return false;
 
   /* Without alias info we can't move around loads.  */
-  if (gimple_references_memory_p (stmt) && !optimize)
+  if (!optimize
+      && gimple_assign_single_p (stmt)
+      && !is_gimple_val (gimple_assign_rhs1 (stmt)))
     return false;
 
   /* Float expressions must go through memory if float-store is on.  */