re PR tree-optimization/84228 (Bogus -Wstringop-truncation warning with -g)

	PR tree-optimization/84228
	* tree-ssa-strlen.c (maybe_diag_stxncpy_trunc): Skip debug statements.

	* c-c++-common/Wstringop-truncation-3.c: New test.

From-SVN: r257411

gcc/ChangeLog

+2018-02-06  Marek Polacek  <polacek@redhat.com>
+
+	PR tree-optimization/84228
+	* tree-ssa-strlen.c (maybe_diag_stxncpy_trunc): Skip debug statements.
+
 2018-02-06  Tamar Christina  <tamar.christina@arm.com>
 
 	PR target/82641

gcc/testsuite/ChangeLog

+2018-02-06  Marek Polacek  <polacek@redhat.com>
+
+	PR tree-optimization/84228
+	* c-c++-common/Wstringop-truncation-3.c: New test.
+
 2018-02-06  Tamar Christina  <tamar.christina@arm.com>
 
 	PR target/82641

gcc/testsuite/c-c++-common/Wstringop-truncation-3.c

+/* PR tree-optimization/84228 */
+/* { dg-do compile } */
+/* { dg-options "-Wstringop-truncation -O2 -g" } */
+
+char *strncpy (char *, const char *, __SIZE_TYPE__);
+struct S
+{
+  char arr[64];
+};
+
+int
+foo (struct S *p1, const char *a)
+{
+  int b = 5, c = 6, d = 7;
+  if (a)
+    goto err;
+  strncpy (p1->arr, a, sizeof p1->arr); /* { dg-bogus "specified bound" } */
+  b = 8; c = 9; d = 10;
+  p1->arr[3] = '\0';
+err:
+  return 0;
+}

gcc/tree-ssa-strlen.c

@@ -1849,7 +1849,7 @@ maybe_diag_stxncpy_trunc (gimple_stmt_iterator gsi, tree src, tree cnt)
 
   /* Look for dst[i] = '\0'; after the stxncpy() call and if found
      avoid the truncation warning.  */
-  gsi_next (&gsi);
+  gsi_next_nondebug (&gsi);
   gimple *next_stmt = gsi_stmt (gsi);
 
   if (!gsi_end_p (gsi) && is_gimple_assign (next_stmt))