re PR tree-optimization/71428 (wrong code with -Os -fno-tree-forwprop (breaks in the .bswap dump))

2016-06-07  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/71428
	* tree-ssa-math-opts.c (perform_symbolic_merge): Properly distinguish
	BIT_FIELD_REF op vs. load.

	* gcc.dg/torture/pr71428.c: New testcase.

From-SVN: r237167

gcc/ChangeLog

 2016-06-07  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/71428
+	* tree-ssa-math-opts.c (perform_symbolic_merge): Properly distinguish
+	BIT_FIELD_REF op vs. load.
+
+2016-06-07  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/71423
 	* match.pd ((X | ~Y) -> Y <= X): Properly invert the comparison
 	for signed ops.

gcc/testsuite/ChangeLog

 2016-06-07  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/71428
+	* gcc.dg/torture/pr71428.c: New testcase.
+
+2016-06-07  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/71423
 	* gcc.dg/torture/pr71423.c: New testcase.
 

gcc/testsuite/gcc.dg/torture/pr71428.c

+/* { dg-do run } */
+/* { dg-additional-options "-fno-tree-forwprop -Wno-psabi -w" } */
+
+typedef unsigned short v64u16 __attribute__ ((vector_size (64)));
+
+v64u16
+foo (v64u16 p1)
+{
+  p1[31] |= p1[1];
+  return p1;
+}
+
+int
+main ()
+{
+  v64u16 x = foo ((v64u16){ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 });
+  if (x[31] != 1)
+    __builtin_abort();
+  return 0;
+}

gcc/tree-ssa-math-opts.c

@@ -2164,10 +2164,12 @@ perform_symbolic_merge (gimple *source_stmt1, struct symbolic_number *n1,
   struct symbolic_number *n_start;
 
   tree rhs1 = gimple_assign_rhs1 (source_stmt1);
-  if (TREE_CODE (rhs1) == BIT_FIELD_REF)
+  if (TREE_CODE (rhs1) == BIT_FIELD_REF
+      && TREE_CODE (TREE_OPERAND (rhs1, 0)) == SSA_NAME)
     rhs1 = TREE_OPERAND (rhs1, 0);
   tree rhs2 = gimple_assign_rhs1 (source_stmt2);
-  if (TREE_CODE (rhs2) == BIT_FIELD_REF)
+  if (TREE_CODE (rhs2) == BIT_FIELD_REF
+      && TREE_CODE (TREE_OPERAND (rhs2, 0)) == SSA_NAME)
     rhs2 = TREE_OPERAND (rhs2, 0);
 
   /* Sources are different, cancel bswap if they are not memory location with