re PR tree-optimization/86363 (wrong code with __builtin_memset() at -O1)

2018-07-02  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/86363
	* tree-ssa-sccvn.c (vn_reference_lookup_3): Check the
	memset argument refers to a non-variable address.

	* gcc.dg/torture/pr86363.c: New testcase.

From-SVN: r262307

gcc/ChangeLog

+2018-07-02  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/86363
+	* tree-ssa-sccvn.c (vn_reference_lookup_3): Check the
+	memset argument refers to a non-variable address.
+
 2018-07-02  Aldy Hernandez  <aldyh@redhat.com>
 
 	* tree-vrp.c (extract_range_from_binary_expr_1): Abstract a lot of the

gcc/testsuite/ChangeLog

+2018-07-02  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/86363
+	* gcc.dg/torture/pr86363.c: New testcase.
+
 2018-07-02  Martin Liska  <mliska@suse.cz>
 
 	* gcc.dg/completion-1.c: New test.

gcc/testsuite/gcc.dg/torture/pr86363.c

+/* { dg-do run } */
+/* { dg-additional-options "-w -Wno-psabi" } */
+
+typedef char U __attribute__ ((vector_size (16)));
+typedef unsigned V __attribute__ ((vector_size (16)));
+
+V g;
+
+V
+f (V v, U u)
+{
+  __builtin_memset (&u[v[0]], 0, 1);
+  g ^= u[0];
+  return g;
+}
+
+int
+main (void)
+{
+  V x = f ((V) { 5 }, (U) { 1 });
+
+  if (x[0] != 1 || x[1] != 1 || x[2] != 1 || x[3] != 1)
+    __builtin_abort ();
+  return 0;
+}

gcc/tree-ssa-sccvn.c

@@ -1988,6 +1988,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_,
 	  base2 = get_ref_base_and_extent (ref2, &offset2, &size2, &maxsize2,
 					   &reverse);
 	  if (!known_size_p (maxsize2)
+	      || !known_eq (maxsize2, size2)
 	      || !operand_equal_p (base, base2, OEP_ADDRESS_OF))
 	    return (void *)-1;
 	}