combine.c (simplify_comparison): If simplifying a logical shift right and compare with constant...

* combine.c (simplify_comparison): If simplifying a logical shift
right and compare with constant, force the comparison to unsigned.

From-SVN: r50400

gcc/ChangeLog

+2002-03-07  Richard Earnshaw  <rearnsha@arm.com>
+
+	* combine.c (simplify_comparison): If simplifying a logical shift
+	right and compare with constant, force the comparison to unsigned.
+
 2002-03-07  Aldy Hernandez  <aldyh@redhat.com>
 
         * doc/invoke.texi: Add documentation for -mabi=no-altivec.

gcc/combine.c

@@ -10885,6 +10885,11 @@ simplify_comparison (code, pop0, pop1)
 		  || (floor_log2 (const_op) + INTVAL (XEXP (op0, 1))
 		      < mode_width)))
 	    {
+	      /* If the shift was logical, then we must make the condition
+		 unsigned.  */
+	      if (GET_CODE (op0) == LSHIFTRT)
+		code = unsigned_condition (code);
+
 	      const_op <<= INTVAL (XEXP (op0, 1));
 	      op1 = GEN_INT (const_op);
 	      op0 = XEXP (op0, 0);