re PR middle-end/87099 (internal compiler error: segmentation fault)

	PR middle-end/87099
	* calls.c (maybe_warn_nonstring_arg): Punt early if
	warn_stringop_overflow is zero.  Don't call get_range_strlen
	on 3rd argument, keep iterating until lenrng[1] is INTEGER_CST.
	Swap comparison operands to have constants on rhs.  Only use
	lenrng[1] if non-NULL and INTEGER_CST.  Don't uselessly
	increment lenrng[0].

	* gcc.dg/pr87099.c: New test.

From-SVN: r263915

gcc/ChangeLog

+2018-08-28  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/87099
+	* calls.c (maybe_warn_nonstring_arg): Punt early if
+	warn_stringop_overflow is zero.  Don't call get_range_strlen
+	on 3rd argument, keep iterating until lenrng[1] is INTEGER_CST.
+	Swap comparison operands to have constants on rhs.  Only use
+	lenrng[1] if non-NULL and INTEGER_CST.  Don't uselessly
+	increment lenrng[0].
+
 2018-08-28  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* tree-ssa-sccvn.c (fully_constant_vn_reference_p): Fix unguarded

gcc/calls.c

@@ -1545,7 +1545,7 @@ maybe_warn_nonstring_arg (tree fndecl, tree exp)
   if (!fndecl || !fndecl_built_in_p (fndecl, BUILT_IN_NORMAL))
     return;
 
-  if (TREE_NO_WARNING (exp))
+  if (TREE_NO_WARNING (exp) || !warn_stringop_overflow)
     return;
 
   unsigned nargs = call_expr_nargs (exp);
@@ -1573,7 +1573,9 @@ maybe_warn_nonstring_arg (tree fndecl, tree exp)
 	   the range of their known or possible lengths and use it
 	   conservatively as the bound for the unbounded function,
 	   and to adjust the range of the bound of the bounded ones.  */
-	for (unsigned argno = 0; argno < nargs && !*lenrng; argno ++)
+	for (unsigned argno = 0;
+	     argno < MIN (nargs, 2)
+	     && !(lenrng[1] && TREE_CODE (lenrng[1]) == INTEGER_CST); argno++)
 	  {
 	    tree arg = CALL_EXPR_ARG (exp, argno);
 	    if (!get_attr_nonstring_decl (arg))
@@ -1585,12 +1587,12 @@ maybe_warn_nonstring_arg (tree fndecl, tree exp)
     case BUILT_IN_STRNCAT:
     case BUILT_IN_STPNCPY:
     case BUILT_IN_STRNCPY:
-      if (2 < nargs)
+      if (nargs > 2)
 	bound = CALL_EXPR_ARG (exp, 2);
       break;
 
     case BUILT_IN_STRNDUP:
-      if (1 < nargs)
+      if (nargs > 1)
 	bound = CALL_EXPR_ARG (exp, 1);
       break;
 
@@ -1600,7 +1602,7 @@ maybe_warn_nonstring_arg (tree fndecl, tree exp)
 	if (!get_attr_nonstring_decl (arg))
 	  get_range_strlen (arg, lenrng);
 
-	if (1 < nargs)
+	if (nargs > 1)
 	  bound = CALL_EXPR_ARG (exp, 1);
 	break;
       }
@@ -1640,11 +1642,9 @@ maybe_warn_nonstring_arg (tree fndecl, tree exp)
 	}
     }
 
-  if (*lenrng)
+  if (lenrng[1] && TREE_CODE (lenrng[1]) == INTEGER_CST)
     {
       /* Add one for the nul.  */
-      lenrng[0] = const_binop (PLUS_EXPR, TREE_TYPE (lenrng[0]),
-			       lenrng[0], size_one_node);
       lenrng[1] = const_binop (PLUS_EXPR, TREE_TYPE (lenrng[1]),
 			       lenrng[1], size_one_node);
 

gcc/testsuite/ChangeLog

+2018-08-28  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/87099
+	* gcc.dg/pr87099.c: New test.
+
 2018-08-28  Richard Sandiford  <richard.sandiford@arm.com>
 
 	PR testsuite/87078

gcc/testsuite/gcc.dg/pr87099.c

+/* PR middle-end/87099 */
+/* { dg-do compile } */
+/* { dg-options "-Wstringop-overflow" } */
+
+void bar (char *);
+
+int
+foo (int n)
+{
+  char v[n];
+  bar (v);
+  return __builtin_strncmp (&v[1], "aaa", 3);
+}
+
+int
+baz (int n, char *s)
+{
+  char v[n];
+  bar (v);
+  return __builtin_strncmp (&v[1], s, 3);
+}