(simplify_and_const_int, case IOR, XOR, NOT): Don't

create constant wider than mode of VAROP.

From-SVN: r4583

diff --git a/gcc/combine.c b/gcc/combine.c
index b254d36b0a634d8ac6539b12fcb7e44ecc9bde26..7a93f2bd515731dad1e9f6d0f2d7f59748c2be62 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -5968,13 +5968,18 @@ simplify_and_const_int (x, mode, varop, constop)
        case XOR:
          /* If VAROP is (ior (lshiftrt FOO C1) C2), try to commute the IOR and
             LSHIFT so we end up with an (and (lshiftrt (ior ...) ...) ...)
-            operation which may be a bitfield extraction.  */
+            operation which may be a bitfield extraction.  Ensure
+            that the constant we form is not wider than the mode of
+            VAROP.  */
 
          if (GET_CODE (XEXP (varop, 0)) == LSHIFTRT
              && GET_CODE (XEXP (XEXP (varop, 0), 1)) == CONST_INT
              && INTVAL (XEXP (XEXP (varop, 0), 1)) >= 0
              && INTVAL (XEXP (XEXP (varop, 0), 1)) < HOST_BITS_PER_WIDE_INT
              && GET_CODE (XEXP (varop, 1)) == CONST_INT
+             && ((INTVAL (XEXP (XEXP (varop, 0), 1))
+                 + floor_log2 (INTVAL (XEXP (varop, 1))))
+                 < GET_MODE_BITSIZE (GET_MODE (varop)))
              && (INTVAL (XEXP (varop, 1))
                  & ~ nonzero_bits (XEXP (varop, 0), GET_MODE (varop)) == 0))
            {
@@ -6003,12 +6008,15 @@ simplify_and_const_int (x, mode, varop, constop)
                                         XEXP (varop, 1), constop))));
 
        case NOT:
-         /* (and (not FOO)) is (and (xor FOO CONST_OP)) so if FOO is an
-            LSHIFTRT we can do the same as above.  */
+         /* (and (not FOO)) is (and (xor FOO CONST)), so if FOO is an
+            LSHIFTRT, we can do the same as above.  Ensure that the constant
+            we form is not wider than the mode of VAROP.  */
 
          if (GET_CODE (XEXP (varop, 0)) == LSHIFTRT
              && GET_CODE (XEXP (XEXP (varop, 0), 1)) == CONST_INT
              && INTVAL (XEXP (XEXP (varop, 0), 1)) >= 0
+             && (INTVAL (XEXP (XEXP (varop, 0), 1)) + floor_log2 (constop)
+                 < GET_MODE_BITSIZE (GET_MODE (varop)))
              && INTVAL (XEXP (XEXP (varop, 0), 1)) < HOST_BITS_PER_WIDE_INT)
            {
              temp = GEN_INT (constop << INTVAL (XEXP (XEXP (varop, 0), 1)));