PR middle-end/85369 - no -Wstringop-overflow for a strcpy / stpcpy call with a…

PR middle-end/85369 - no -Wstringop-overflow for a strcpy / stpcpy call with a nonstring pointer when providing movstr pattern

gcc/ChangeLog:

	PR middle-end/85369
	* builtins.c (expand_builtin_stpcpy_1): New function.
	(expand_builtin_stpcpy): Call it, and call maybe_warn_nonstring_arg
	only if the former succeeds.

From-SVN: r260976

gcc/ChangeLog

+2018-05-30  Martin Sebor  <msebor@redhat.com>
+
+	PR middle-end/85369
+	* builtins.c (expand_builtin_stpcpy_1): New function.
+	(expand_builtin_stpcpy): Call it, and call maybe_warn_nonstring_arg
+	only if the former succeeds.
+
 2018-05-31 Sameera Deshpande <sameera.deshpande@linaro.org>
 
 	* config/aarch64/aarch64-cores.def (saphira) : Add support for ARMv8.4

gcc/builtins.c

@@ -3814,7 +3814,7 @@ expand_builtin_strcpy_args (tree dest, tree src, rtx target)
    mode MODE if that's convenient).  */
 
 static rtx
-expand_builtin_stpcpy (tree exp, rtx target, machine_mode mode)
+expand_builtin_stpcpy_1 (tree exp, rtx target, machine_mode mode)
 {
   tree dst, src;
   location_t loc = EXPR_LOCATION (exp);
@@ -3891,6 +3891,25 @@ expand_builtin_stpcpy (tree exp, rtx target, machine_mode mode)
     }
 }
 
+/* Expand a call EXP to the stpcpy builtin and diagnose uses of nonstring
+   arguments while being careful to avoid duplicate warnings (which could
+   be issued if the expander were to expand the call, resulting in it
+   being emitted in expand_call().  */
+
+static rtx
+expand_builtin_stpcpy (tree exp, rtx target, machine_mode mode)
+{
+  if (rtx ret = expand_builtin_stpcpy_1 (exp, target, mode))
+    {
+      /* The call has been successfully expanded.  Check for nonstring
+	 arguments and issue warnings as appropriate.  */
+      maybe_warn_nonstring_arg (get_callee_fndecl (exp), exp);
+      return ret;
+    }
+
+  return NULL_RTX;
+}
+
 /* Check a call EXP to the stpncpy built-in for validity.
    Return NULL_RTX on both success and failure.  */