(simplify_binary_operation): Insure that folded >> extends

the sign even if the host bootstrap compiler doesn't.

From-SVN: r2446

diff --git a/gcc/cse.c b/gcc/cse.c
index 89cd43316e0dd788cda33d1831c7d1512dff2ac9..12255b0e76900e148556f03abc4e3e1e647e6cc2 100644 (file)
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -3964,6 +3964,12 @@ simplify_binary_operation (code, mode, op0, op1)
        return 0;
 
       val = arg0s >> arg1;
+
+      /* Bootstrap compiler may not have sign extended the right shift.
+        Manually extend the sign to insure bootstrap cc matches gcc.  */
+      if (arg0s < 0 && arg1 > 0)
+       val |= ((HOST_WIDE_INT) -1) << (HOST_BITS_PER_WIDE_INT - arg1);
+
       break;
 
     case ROTATERT: