Use unsigned shift instead of signed shift.

From-SVN: r29621

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4cec47e..aee30b9 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Thu Sep 23 15:54:12 1999  Nick Clifton  <nickc@cygnus.com>
+
+       * combine.c (simplify_comparison): Use an unsigned shift to adjust
+       the constant.
+
 Thu Sep 23 08:46:21 1999  Guy Harris  <guy@netapp.com>
 
        * gcc.1: Fix a formatting error.

diff --git a/gcc/combine.c b/gcc/combine.c
index 6c24caa..0e556db 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -10362,8 +10362,12 @@ simplify_comparison (code, pop0, pop1)
                  & ~ (mask >> (INTVAL (XEXP (op0, 1))
                                + ! equality_comparison_p))) == 0)
            {
-             const_op >>= INTVAL (XEXP (op0, 1));
-             op1 = GEN_INT (const_op);
+             /* We must perform a logical shift, not an arithmetic one,
+                as we want the top N bits of C to be zero.  */
+             unsigned HOST_WIDE_INT temp = const_op;
+             
+             temp >>= INTVAL (XEXP (op0, 1));
+             op1 = GEN_INT (temp);
              op0 = XEXP (op0, 0);
              continue;
            }