--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr93582-11.c	Mon May 25 07:50:57 2020 +0900
@@ -0,0 +1,16 @@
+/* PR tree-optimization/93582 */
+/* { dg-do compile { target lp64 } } */
+/* { dg-options "-O2 -fdump-tree-fre1" } */
+/* { dg-final { scan-tree-dump "return 9223372036854775806;" "fre1" } } */
+
+union U { struct A { unsigned long long a : 1, b : 62, c : 1; } a; unsigned long long i; };
+
+unsigned long long
+foo (char *p)
+{
+  __builtin_memset (p - 0xfffffffffffffffULL, 0, 0xffffffffffffffeULL);
+  __builtin_memset (p + 1, 0, 0xffffffffffffffeULL);
+  union U *q = (union U *) (void *) (p - 4);
+  q->a.b = -1;
+  return q->i;
+}