--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/strlenopt-37.c	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,83 @@
+/* PR tree-optimization/78450 - strlen(s) return value can be assumed
+   to be less than the size of s
+   { dg-do compile }
+   { dg-options "-O2 -fdump-tree-optimized" } */
+
+#include "strlenopt.h"
+
+extern char ax[];
+
+struct MemArray7 { char a7[7]; };
+struct MemArray6 { char a6[6]; };
+struct MemArray5 { char a5[5]; };
+struct MemArray4 { char a4[4]; };
+struct MemArray3 { char a3[3]; };
+struct MemArray2 { char a2[2]; };
+struct MemArray1 { char a1[1]; };
+struct MemArray0 { int n; char a0[0]; };
+struct MemArrayX { int n; char ax[]; };
+
+struct MemArrays
+{
+  struct MemArray7 *ma7;
+  struct MemArray6 *ma6;
+  struct MemArray5 *ma5;
+  struct MemArray4 *ma4;
+  struct MemArray3 *ma3;
+  struct MemArray2 *ma2;
+  struct MemArray1 *ma1;
+  struct MemArray0 *ma0;
+  struct MemArrayX *max;
+};
+
+extern void if_stmt_on_line (int);
+extern void else_stmt_on_line (int);
+
+#define T(expr)								\
+  (!!(expr) ? if_stmt_on_line (__LINE__) : else_stmt_on_line (__LINE__))
+
+void test_memarray_lt (struct MemArrays *p)
+{
+  T (strlen (p->ma7->a7) < sizeof p->ma7->a7);
+  T (strlen (p->ma6->a6) < sizeof p->ma6->a6);
+  T (strlen (p->ma5->a5) < sizeof p->ma5->a5);
+  T (strlen (p->ma4->a4) < sizeof p->ma4->a4);
+  T (strlen (p->ma3->a3) < sizeof p->ma3->a3);
+  T (strlen (p->ma2->a2) < sizeof p->ma2->a2);
+  T (strlen (p->ma1->a1) < sizeof p->ma1->a1);
+
+  T (strlen (p->ma0->a0) < 1);
+  T (strlen (p->max->ax) < 1);
+}
+
+void test_memarray_eq (struct MemArrays *p)
+{
+  T (strlen (p->ma7->a7) == sizeof p->ma7->a7);
+  T (strlen (p->ma6->a6) == sizeof p->ma6->a6);
+  T (strlen (p->ma5->a5) == sizeof p->ma5->a5);
+  T (strlen (p->ma4->a4) == sizeof p->ma4->a4);
+  T (strlen (p->ma3->a3) == sizeof p->ma3->a3);
+  T (strlen (p->ma2->a2) == sizeof p->ma2->a2);
+  T (strlen (p->ma1->a1) == sizeof p->ma1->a1);
+
+  T (strlen (p->ma0->a0) == 1);
+  T (strlen (p->max->ax) == 1);
+}
+
+void test_memarray_gt (struct MemArrays *p)
+{
+  T (strlen (p->ma7->a7) > sizeof p->ma7->a7);
+  T (strlen (p->ma6->a6) > sizeof p->ma6->a6);
+  T (strlen (p->ma5->a5) > sizeof p->ma5->a5);
+  T (strlen (p->ma4->a4) > sizeof p->ma4->a4);
+  T (strlen (p->ma3->a3) > sizeof p->ma3->a3);
+  T (strlen (p->ma2->a2) > sizeof p->ma2->a2);
+  T (strlen (p->ma1->a1) > sizeof p->ma1->a1);
+
+  T (strlen (p->ma0->a0) > 1);
+  T (strlen (p->max->ax) > 1);
+ }
+
+/* Verify that no if or else statements have been eliminated.
+   { dg-final { scan-tree-dump-times "if_stmt_on_line" 27 "optimized" } }
+   { dg-final { scan-tree-dump-times "else_stmt_on_line" 27 "optimized" } }  */