re PR middle-end/56559 (ICE in propagate_op_to_single_use, at tree-ssa-reassoc.c:1057)

	PR tree-optimization/56559
	* tree-ssa-reassoc.c (zero_one_operation): When looking at rhs2,
	check that it has only a single use.

	* gcc.dg/tree-ssa/reassoc-26.c: New test.

From-SVN: r196520

gcc/ChangeLog

+2013-03-07  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/56559
+	* tree-ssa-reassoc.c (zero_one_operation): When looking at rhs2,
+	check that it has only a single use.
+
 2013-03-07  Richard Biener  <rguenther@suse.de>
 
 	* doc/invoke.texi (fwhole-program): Discourage use in combination

gcc/testsuite/ChangeLog

+2013-03-07  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/56559
+	* gcc.dg/tree-ssa/reassoc-26.c: New test.
+
 2013-03-07  Andreas Schwab  <schwab@suse.de>
 
 	* gcc.dg/pr31490.c: Fix last change.

gcc/testsuite/gcc.dg/tree-ssa/reassoc-26.c

+/* PR tree-optimization/56559 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math" } */
+
+double a, b, c, d, e;
+
+void
+foo ()
+{
+  a = e * e;
+  b = d * e + c * e * a;
+}

gcc/tree-ssa-reassoc.c

@@ -1107,7 +1107,8 @@ zero_one_operation (tree *def, enum tree_code opcode, tree op)
 	 the operand might be hiding in the rightmost one.  */
       if (opcode == MULT_EXPR
 	  && gimple_assign_rhs_code (stmt) == opcode
-	  && TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME)
+	  && TREE_CODE (gimple_assign_rhs2 (stmt)) == SSA_NAME
+	  && has_single_use (gimple_assign_rhs2 (stmt)))
 	{
 	  gimple stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs2 (stmt));
 	  if (stmt_is_power_of_op (stmt2, op))