On Wed, Jul 13, 2011 at 9:33 AM, Kai Tietz <ktiet...@googlemail.com> wrote:
> Hello,
>
> This patch adds support to fold_binary_loc for one-bit precision
> typed bitwise-or expression.
Seems to be a fallout of the missing TRUTH_NOT conversion as well.
> ChangeLog
>
> 2011-07-13 Kai Tietz <kti...@redhat.com>
>
> * fold-const.c (fold_binary_loc): Add
> support for one-bit bitwise-or 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 08:23:29.000000000 +0200
> +++ gcc/gcc/fold-const.c 2011-07-13 08:59:04.011620200 +0200
> @@ -10688,6 +10688,52 @@ fold_binary_loc (location_t loc,
> return omit_one_operand_loc (loc, type, t1, arg0);
> }
>
> + if (TYPE_PRECISION (type) == 1 && INTEGRAL_TYPE_P (type))
> + {
> + /* If arg0 is constant zero, drop it. */
> + if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
> + return non_lvalue_loc (loc, fold_convert_loc (loc, type, arg1));
> + if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
> + return omit_one_operand_loc (loc, type, arg0, arg1);
> +
> + /* !X | X is always true. ~X | X is always true. */
> + 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_one_node, arg1);
> + /* X | !X is always true. X | ~X is always true. */
> + 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_one_node, arg0);
> +
> + /* (X & !Y) | (!X & Y) is X ^ Y */
> + if (TREE_CODE (arg0) == BIT_AND_EXPR
> + && TREE_CODE (arg1) == BIT_AND_EXPR)
> + {
> + tree a0, a1, l0, l1, n0, n1;
> +
> + a0 = fold_convert_loc (loc, type, TREE_OPERAND (arg1, 0));
> + a1 = fold_convert_loc (loc, type, TREE_OPERAND (arg1, 1));
> +
> + l0 = fold_convert_loc (loc, type, TREE_OPERAND (arg0, 0));
> + l1 = fold_convert_loc (loc, type, TREE_OPERAND (arg0, 1));
> +
> + n0 = fold_build1_loc (loc, TRUTH_NOT_EXPR, type, l0);
> + n1 = fold_build1_loc (loc, TRUTH_NOT_EXPR, type, l1);
> +
> + if ((operand_equal_p (n0, a0, 0)
> + && operand_equal_p (n1, a1, 0))
> + || (operand_equal_p (n0, a1, 0)
> + && operand_equal_p (n1, a0, 0)))
> + return fold_build2_loc (loc, BIT_XOR_EXPR, type, l0, n1);
> + }
> +
> + tem = fold_truth_andor (loc, code, type, arg0, arg1, op0, op1);
> + if (tem)
> + return tem;
> + }
> +
> /* Canonicalize (X & C1) | C2. */
> if (TREE_CODE (arg0) == BIT_AND_EXPR
> && TREE_CODE (arg1) == INTEGER_CST
>
