From: Nick Clifton <nickc@cygnus.com>
Date: Thu, 23 Sep 1999 14:58:54 +0000 (+0000)
Subject: Use unsigned shift instead of signed shift.
X-Git-Tag: prereleases/libstdc++-2.92~10401
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7ce787fe030a2bf16a49cb5a30e6bb521e6507e7;p=thirdparty%2Fgcc.git

Use unsigned shift instead of signed shift.

From-SVN: r29621
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4cec47efc068..aee30b902785 100644
--- 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 6c24caa9afe7..0e556db4ab9b 100644
--- 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;
 	    }