- critical fix / wrong-code.

  [4.1 regression] -1073741824 <= n && n <= 1073741823 is true
                   where n is 1073741824

Changed files:
    gcc-pr22429.patch -> 1.1

diff --git a/gcc-pr22429.patch b/gcc-pr22429.patch
new file mode 100644 (file)
index 0000000..beda5b8
--- /dev/null
+++ b/gcc-pr22429.patch
@@ -0,0 +1,40 @@
+The problem here is fold (build_range_check) converts
+"-1073741824 <= n && n <= 1073741823" to "n + 1073741824 >= 0"
+which makes depends on signed overflow being defined.  Fold later converts
+it to "n >= -1073741824" by my recent patch which is wrong.
+This patch fixes the problem by using unsigned types if signed overflow
+is undefined.
+
+OK? Bootstrapped and tested on x86_64-pc-linux-gnu with no regressions.
+
+Thanks,
+Andrew Pinski
+
+       * fold-const.c (build_range_check): Use unsigned when signed
+       overflow is undefined also.  If etype is subtype, make sure that
+       the subtraction is in the supper type.
+
+--- a/gcc/fold-const.c 2005-10-19 08:15:39.000000000 +0000
++++ b/gcc/fold-const.c 2005-10-19 08:29:46.574021728 +0000
+@@ -4005,7 +4005,8 @@
+     }
+ 
+   value = const_binop (MINUS_EXPR, high, low, 0);
+-  if (value != 0 && TREE_OVERFLOW (value) && ! TYPE_UNSIGNED (etype))
++  if (value != 0 && (!flag_wrapv || TREE_OVERFLOW (value))
++      && ! TYPE_UNSIGNED (etype))
+     {
+       tree utype, minv, maxv;
+ 
+@@ -4016,6 +4017,11 @@
+       case INTEGER_TYPE:
+       case ENUMERAL_TYPE:
+       case CHAR_TYPE:
++        /* There is no requirement that LOW be within the range of ETYPE
++           if the latter is a subtype.  It must, however, be within the base
++           type of ETYPE.  So be sure we do the subtraction in that type.  */
++        if (TREE_TYPE (etype))
++          etype = TREE_TYPE (etype);
+         utype = lang_hooks.types.unsigned_type (etype);
+         maxv = fold_convert (utype, TYPE_MAX_VALUE (etype));
+         maxv = range_binop (PLUS_EXPR, NULL_TREE, maxv, 1,