SOURCES: gcc-pr22429.patch (NEW) - critical fix / wrong-code. [4...

[pluto]

Author: pluto                        Date: Wed Oct 19 08:52:08 2005 GMT
Module: SOURCES                       Tag: HEAD
---- Log message:
- critical fix / wrong-code.
  [4.1 regression] -1073741824 <= n && n <= 1073741823 is true
                   where n is 1073741824

---- Files affected:
SOURCES:
   gcc-pr22429.patch (NONE -> 1.1)  (NEW)

---- Diffs:

================================================================
Index: SOURCES/gcc-pr22429.patch
diff -u /dev/null SOURCES/gcc-pr22429.patch:1.1
--- /dev/null	Wed Oct 19 10:52:08 2005
+++ SOURCES/gcc-pr22429.patch	Wed Oct 19 10:52:03 2005
@@ -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,
================================================================