--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/builtin-memchr-2.c	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,55 @@
+/* Verify that memchr calls with the address of a constant character
+   are folded as expected even at -O0.
+  { dg-do compile }
+  { dg-options "-O0 -Wall -fdump-tree-gimple" } */
+
+typedef __SIZE_TYPE__  size_t;
+typedef __WCHAR_TYPE__ wchar_t;
+
+extern void* memchr (const void*, int, size_t);
+extern int printf (const char*, ...);
+extern void abort (void);
+
+#define A(expr)							\
+  ((expr)							\
+   ? (void)0							\
+   : (printf ("assertion failed on line %i: %s\n",		\
+			__LINE__, #expr),			\
+      abort ()))
+
+const char nul = 0;
+const char cha = 'a';
+
+const struct
+{
+  char c;
+} snul = { 0 },
+  schb = { 'b' },
+  sarr[] = {
+  { 0 },
+  { 'c' }
+  };
+
+
+void test_memchr_cst_char (void)
+{
+  A (&nul == memchr (&nul, 0, 1));
+  A (!memchr (&nul, 'a', 1));
+
+  A (&cha == memchr (&cha, 'a', 1));
+  A (!memchr (&cha, 0, 1));
+
+  A (&snul.c == memchr (&snul.c, 0, 1));
+  A (!memchr (&snul.c, 'a', 1));
+
+  A (&schb.c == memchr (&schb.c, 'b', 1));
+  A (!memchr (&schb.c, 0, 1));
+
+  A (&sarr[0].c == memchr (&sarr[0].c, 0, 1));
+  A (!memchr (&sarr[0].c, 'a', 1));
+
+  A (&sarr[1].c == memchr (&sarr[1].c, 'c', 1));
+  A (!memchr (&sarr[1].c, 0, 1));
+}
+
+/* { dg-final { scan-tree-dump-not "abort" "gimple" } } */