re PR other/83508 ([arm] c-c++-common/Wrestrict.c fails since r255836)

PR other/83508
	* builtins.c (check_access): Avoid warning when the no-warning bit
	is set.

	PR other/83508
	* gcc.dg/Wstringop-overflow-2.c: New test.

From-SVN: r256683

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2018-01-14  Martin Sebor  <msebor@redhat.com>
+
+	PR other/83508
+	* builtins.c (check_access): Avoid warning when the no-warning bit
+	is set.
+
 2018-01-14  Cory Fields  <cory-nospam-@coryfields.com>
 
 	* tree-ssa-loop-im.c (sort_bbs_in_loop_postorder_cmp): Stabilize sort.

gcc/builtins.c

@@ -3154,6 +3154,9 @@ check_access (tree exp, tree, tree, tree dstwrite,
 	      || (tree_fits_uhwi_p (dstwrite)
 		  && tree_int_cst_lt (dstwrite, range[0]))))
 	{
+	  if (TREE_NO_WARNING (exp))
+	    return false;
+
 	  location_t loc = tree_nonartificial_location (exp);
 	  loc = expansion_point_location_if_in_system_header (loc);
 
@@ -3213,6 +3216,9 @@ check_access (tree exp, tree, tree, tree dstwrite,
 
 	  if (tree_int_cst_lt (maxobjsize, range[0]))
 	    {
+	      if (TREE_NO_WARNING (exp))
+		return false;
+
 	      /* Warn about crazy big sizes first since that's more
 		 likely to be meaningful than saying that the bound
 		 is greater than the object size if both are big.  */
@@ -3234,6 +3240,9 @@ check_access (tree exp, tree, tree, tree dstwrite,
 
 	  if (dstsize != maxobjsize && tree_int_cst_lt (dstsize, range[0]))
 	    {
+	      if (TREE_NO_WARNING (exp))
+		return false;
+
 	      if (tree_int_cst_equal (range[0], range[1]))
 		warning_at (loc, opt,
 			    "%K%qD specified bound %E "
@@ -3257,6 +3266,9 @@ check_access (tree exp, tree, tree, tree dstwrite,
       && dstwrite && range[0]
       && tree_int_cst_lt (slen, range[0]))
     {
+      if (TREE_NO_WARNING (exp))
+	return false;
+
       location_t loc = tree_nonartificial_location (exp);
 
       if (tree_int_cst_equal (range[0], range[1]))

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2018-01-10  Martin Sebor  <msebor@redhat.com>
+
+	PR other/83508
+	* gcc.dg/Wstringop-overflow-2.c: New test.
+
 2018-01-14  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libgfortran/83811

gcc/testsuite/gcc.dg/Wstringop-overflow-2.c

@@ -0,0 +1,30 @@
+/* PR tree-optimization/83508 - c-c++-common/Wrestrict.c fails since r255836
+   Test to verify that only one of -Wrestrict and -Wstringop-overflow is
+   issued for a problem where either would be appropriate.
+   { dg-do compile }
+   { dg-options "-O2 -Wrestrict -Wstringop-overflow" } */
+
+#define DIFF_MAX __PTRDIFF_MAX__
+
+typedef __PTRDIFF_TYPE__ ptrdiff_t;
+typedef __SIZE_TYPE__ size_t;
+
+void sink (void*);
+
+void f (ptrdiff_t i, size_t n)
+{
+  if (i < DIFF_MAX - 2 || DIFF_MAX - 1 > i)
+    i = DIFF_MAX - 2;
+
+  if (n < 4 || 5 < n)
+    n = 4;
+
+  char a[8] = "012";
+
+  /* The following could very well be diagnosed by -Wstringop-overflow
+     instead but there's no way to verify that only one of the two
+     warnings is issued and the choice of -Wrestrict simply reflects
+     the fact that -Wrestrict runs before -Wstringop-overflow.  */
+  __builtin_strncpy (a + i, a, n);   /* { dg-warning "\\\[-Wrestrict]" } */
+  sink (a);
+}