re PR tree-optimization/84238 (ICE tree check: expected integer_cst, have…

re PR tree-optimization/84238 (ICE tree check: expected integer_cst, have plus_expr in to_wide, at tree.h:5527)

	PR tree-optimization/84238
	* tree-ssa-strlen.c (maybe_diag_stxncpy_trunc): Verify the result of
	get_range_strlen.

	* gcc.dg/Wstringop-overflow-3.c: New test.

From-SVN: r257497

gcc/ChangeLog

+2018-02-08  Marek Polacek  <polacek@redhat.com>
+
+	PR tree-optimization/84238
+	* tree-ssa-strlen.c (maybe_diag_stxncpy_trunc): Verify the result of
+	get_range_strlen.
+
 2018-02-08  Richard Sandiford  <richard.sandiford@linaro.org>
 
 	PR tree-optimization/84265

gcc/testsuite/ChangeLog

+2018-02-08  Marek Polacek  <polacek@redhat.com>
+
+	PR tree-optimization/84238
+	* gcc.dg/Wstringop-overflow-3.c: New test.
+
 2018-02-08  Nathan Sidwell  <nathan@acm.org>
 
 	* g++.dg/cpp0x/initlist93.C: Adjust diagnostic.

gcc/testsuite/gcc.dg/Wstringop-overflow-3.c

+/* PR tree-optimization/84238 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+char a[1];
+int b;
+char *strncpy (char *, char *, __SIZE_TYPE__);
+void
+c ()
+{
+  char d[b];
+  strncpy (a, &d[3], 3); /* { dg-warning "writing 3 bytes into a region of size 1" } */
+}

gcc/tree-ssa-strlen.c

@@ -1899,7 +1899,10 @@ maybe_diag_stxncpy_trunc (gimple_stmt_iterator gsi, tree src, tree cnt)
     {
       tree range[2];
       get_range_strlen (src, range);
-      if (range[0])
+      if (range[0] != NULL_TREE
+	  && TREE_CODE (range[0]) == INTEGER_CST
+	  && range[1] != NULL_TREE
+	  && TREE_CODE (range[1]) == INTEGER_CST)
 	{
 	  lenrange[0] = wi::to_wide (range[0], prec);
 	  lenrange[1] = wi::to_wide (range[1], prec);