+2002-03-23 Alan Modra <amodra@bigpond.net.au>
+
+ * combine.c (simplify_comparison): When widening modes, ignore
+ sign extension on CONST_INTs.
+
2002-03-22 Bob Wilson <bob.wilson@acm.org>
* config/xtensa/xtensa.c (print_operand): Fix incorrect mode
tmode = GET_MODE_WIDER_MODE (tmode))
if (have_insn_for (COMPARE, tmode))
{
+ int zero_extended;
+
/* If the only nonzero bits in OP0 and OP1 are those in the
narrower mode and this is an equality or unsigned comparison,
we can use the wider mode. Similarly for sign-extended
values, in which case it is true for all comparisons. */
- if (((code == EQ || code == NE
- || code == GEU || code == GTU || code == LEU || code == LTU)
- && (nonzero_bits (op0, tmode) & ~GET_MODE_MASK (mode)) == 0
- && (nonzero_bits (op1, tmode) & ~GET_MODE_MASK (mode)) == 0)
+ zero_extended = ((code == EQ || code == NE
+ || code == GEU || code == GTU
+ || code == LEU || code == LTU)
+ && (nonzero_bits (op0, tmode)
+ & ~GET_MODE_MASK (mode)) == 0
+ && ((GET_CODE (op1) == CONST_INT
+ || (nonzero_bits (op1, tmode)
+ & ~GET_MODE_MASK (mode)) == 0)));
+
+ if (zero_extended
|| ((num_sign_bit_copies (op0, tmode)
> GET_MODE_BITSIZE (tmode) - GET_MODE_BITSIZE (mode))
&& (num_sign_bit_copies (op1, tmode)
XEXP (op0, 1)));
op0 = gen_lowpart_for_combine (tmode, op0);
+ if (zero_extended && GET_CODE (op1) == CONST_INT)
+ op1 = GEN_INT (INTVAL (op1) & GET_MODE_MASK (mode));
op1 = gen_lowpart_for_combine (tmode, op1);
break;
}