[backport from gcc-4.8/trunk r192322 <mikpe@it.uu.se>]

gcc/

2012-10-10  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/54877
	* tree-vect-loop.c (vect_is_simple_reduction_1): For MINUS_EXPR
	use make_ssa_name instead of copy_ssa_name.

gcc/testsuite/

2012-10-10  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/54877
	* gcc.dg/torture/pr54877.c: New test.

--- gcc-4.7.2/gcc/testsuite/gcc.dg/torture/pr54877.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.7.2/gcc/testsuite/gcc.dg/torture/pr54877.c	2012-10-13 10:28:06.000000000 +0200
@@ -0,0 +1,23 @@
+/* PR tree-optimization/54877 */
+/* { dg-do run } */
+/* { dg-options "-ffast-math" } */
+
+extern void abort (void);
+
+int
+foo (void)
+{
+  double d;
+  int i;
+  for (i = 0, d = 0; i < 64; i++)
+    d--;
+  return (int) d;
+}
+
+int
+main ()
+{
+  if (foo () != -64)
+    abort ();
+  return 0;
+}
--- gcc-4.7.2/gcc/tree-vect-loop.c.~1~	2012-08-06 16:34:27.000000000 +0200
+++ gcc-4.7.2/gcc/tree-vect-loop.c	2012-10-13 10:27:46.000000000 +0200
@@ -2257,7 +2257,7 @@ vect_is_simple_reduction_1 (loop_vec_inf
   if (orig_code == MINUS_EXPR)
     {
       tree rhs = gimple_assign_rhs2 (def_stmt);
-      tree negrhs = make_ssa_name (SSA_NAME_VAR (rhs), NULL);
+      tree negrhs = make_ssa_name (TREE_TYPE (rhs), NULL);
       gimple negate_stmt = gimple_build_assign_with_ops (NEGATE_EXPR, negrhs,
 							 rhs, NULL);
       gimple_stmt_iterator gsi = gsi_for_stmt (def_stmt);