PR tree-optimization/88659 - ICE in maybe_warn_nonstring_arg

gcc/ChangeLog:
	* calls.c (maybe_warn_nonstring_arg): Avoid assuming maxlen is set.

gcc/testsuite/ChangeLog:
	* gcc.dg/Wstringop-truncation-6.c: New test.

From-SVN: r267569

gcc/ChangeLog

@@ -1,3 +1,8 @@
+2019-01-03  Martin Sebor  <msebor@redhat.com>
+
+	PR tree-optimization/88659
+	* calls.c (maybe_warn_nonstring_arg): Avoid assuming maxlen is set.
+
 2019-01-03  Aaron Sawdey  <acsawdey@linux.ibm.com>
 
 	* config/rs6000/rs6000-string.c (expand_block_move): Don't use

gcc/calls.c

@@ -1681,7 +1681,7 @@ maybe_warn_nonstring_arg (tree fndecl, tree exp)
 	  bndrng[1] = maxlen;
 	  bound = void_type_node;
 	}
-      else
+      else if (maxlen)
 	{
 	  /* Replace the bound on the operation with the upper bound
 	     of the length of the string if the latter is smaller.  */

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2019-01-03  Martin Sebor  <msebor@redhat.com>
+
+	PR tree-optimization/88659
+	* gcc.dg/Wstringop-truncation-6.c: New test.
+
 2019-01-02  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	PR fortran/48543

gcc/testsuite/gcc.dg/Wstringop-truncation-6.c

@@ -0,0 +1,42 @@
+/* PR tree-optimization/88659 - ICE in maybe_warn_nonstring_arg
+   { dg-do compile }
+   { dg-options "-O0 -Wall" }  */
+
+const char a[5] = "1234";
+
+int cst_idx_cst_bnd (void)
+{
+  return __builtin_strnlen (&a[1], 0);
+}
+
+int var_idx_cst_bnd (void)
+{
+  int i = 1;
+  return __builtin_strnlen (&a[i], 0);
+}
+
+int phi_idx_cst_bnd (int i)
+{
+  return __builtin_strnlen (&a[i ? 1 : 2], 0);
+}
+
+int unk_idx_cst_bnd (int i)
+{
+  return __builtin_strnlen (&a[i], 0);
+}
+
+int cst_idx_var_bnd (void)
+{
+  int n = 0;
+  return __builtin_strnlen (&a[1], n);
+}
+
+int cst_idx_phi_bnd (int n)
+{
+  return __builtin_strnlen (&a[1], n ? 1 : 2);
+}
+
+int cst_idx_unk_bnd (int n)
+{
+  return __builtin_strnlen (&a[1], n);
+}