2016-02-26  Jakub Jelinek  <jakub@redhat.com>
	    Eric Botcazou  <ebotcazou@adacore.com>

	PR rtl-optimization/69891
	* dse.c (scan_insn): If we can't figure out memset arguments
	or they are non-constant, call clear_rhs_from_active_local_stores.

--- gcc/testsuite/gcc.target/i386/pr69891.c	(nonexistent)
+++ gcc/testsuite/gcc.target/i386/pr69891.c	(revision 238137)
@@ -0,0 +1,30 @@
+/* PR rtl-optimization/69891 */
+/* { dg-do run } */
+/* { dg-options "-O -fno-tree-fre -mstringop-strategy=libcall -Wno-psabi" } */
+/* { dg-additional-options "-mno-sse" { target ia32 } } */
+
+typedef unsigned short A;
+typedef unsigned short B __attribute__ ((vector_size (32)));
+typedef unsigned int C;
+typedef unsigned int D __attribute__ ((vector_size (32)));
+typedef unsigned long long E;
+typedef unsigned long long F __attribute__ ((vector_size (32)));
+
+__attribute__((noinline, noclone)) unsigned
+foo(D a, B b, D c, F d)
+{
+  b /= (B) {1, -c[0]} | 1;
+  c[0] |= 7;
+  a %= c | 1;
+  c ^= c;
+  return a[0] + b[15] + c[0] + d[3];
+}
+
+int
+main ()
+{
+  unsigned x = foo ((D) {}, (B) {}, (D) {}, (F) {});
+  if (x != 0)
+    __builtin_abort ();
+  return 0;
+}
--- gcc/dse.c	(revision 238136)
+++ gcc/dse.c	(revision 238137)
@@ -2582,6 +2582,8 @@
 		      active_local_stores = insn_info;
 		    }
 		}
+	      else
+		clear_rhs_from_active_local_stores ();
 	    }
 	}