On Wed, Jul 13, 2011 at 9:34 AM, Kai Tietz <ktiet...@googlemail.com> wrote:
> Hello,
>
> This patch adds support to fold_binary_loc for one-bit precision
> typed bitwise-and expression.
Similar ... your patch descriptions are useless btw.
> ChangeLog
>
> 2011-07-13 Kai Tietz <kti...@redhat.com>
>
> * fold-const.c (fold_binary_loc): Add
> support for one-bit bitwise-and optimizeation.
>
> Bootstrapped and regression tested with prior patches of this series
> for x86_64-pc-linux-gnu.
> Ok for apply?
>
> Regards,
> Kai
>
> Index: gcc/gcc/fold-const.c
> ===================================================================
> --- gcc.orig/gcc/fold-const.c 2011-07-13 08:43:37.000000000 +0200
> +++ gcc/gcc/fold-const.c 2011-07-13 08:58:38.692620200 +0200
> @@ -11062,6 +11062,48 @@ fold_binary_loc (location_t loc,
> if (operand_equal_p (arg0, arg1, 0))
> return non_lvalue_loc (loc, fold_convert_loc (loc, type, arg0));
>
> + if (TYPE_PRECISION (type) == 1 && INTEGRAL_TYPE_P (type))
> + {
> + if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
> + return non_lvalue_loc (loc, fold_convert_loc (loc, type, arg1));
> + if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
> + return non_lvalue_loc (loc, fold_convert_loc (loc, type, arg0));
> + /* Likewise for first arg. */
> + if (integer_zerop (arg0))
> + return omit_one_operand_loc (loc, type, arg0, arg1);
> +
> + /* !X & X is always false. ~X & X is always false. */
> + if ((TREE_CODE (arg0) == TRUTH_NOT_EXPR
> + || TREE_CODE (arg0) == BIT_NOT_EXPR)
> + && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0))
> + return omit_one_operand_loc (loc, type, integer_zero_node, arg1);
> + /* X & !X is always false. X & ~X is always false. */
> + if ((TREE_CODE (arg1) == TRUTH_NOT_EXPR
> + || TREE_CODE (arg1) == BIT_NOT_EXPR)
> + && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
> + return omit_one_operand_loc (loc, type, integer_zero_node, arg0);
> +
> + /* (A < X) & (A + 1 > Y) ==> (A < X) & (A >= Y). Normally
> + A + 1 > Y means (A >= Y) & (A != MAX), but in this case
> + we know that A < X <= MAX. */
> +
> + if (!TREE_SIDE_EFFECTS (arg0) && !TREE_SIDE_EFFECTS (arg1))
> + {
> + tem = fold_to_nonsharp_ineq_using_bound (loc, arg0, arg1);
> + if (tem && !operand_equal_p (tem, arg0, 0))
> + return fold_build2_loc (loc, code, type, tem, arg1);
> +
> + tem = fold_to_nonsharp_ineq_using_bound (loc, arg1, arg0);
> + if (tem && !operand_equal_p (tem, arg1, 0))
> + return fold_build2_loc (loc, code, type, arg0, tem);
> + }
> +
> + tem = fold_truth_andor (loc, code, type, arg0, arg1, op0, op1);
> + if (tem)
> + return tem;
> +
> + }
> +
> /* ~X & X, (X == 0) & X, and !X & X are always zero. */
> if ((TREE_CODE (arg0) == BIT_NOT_EXPR
> || TREE_CODE (arg0) == TRUTH_NOT_EXPR
>
