On Wed, Jul 13, 2011 at 9:32 AM, Kai Tietz <ktiet...@googlemail.com> wrote:
> Hello,
>
> This patch adds support to fold_range_test and to fold_truthop for
> one-bit precision
> typed bitwise-binary and bitwise-not expressions.
This looks reasonable but I'd like to see testcases excercising the
foldings (by scanning the .original dump).
Richard.
> ChangeLog
>
> 2011-07-13 Kai Tietz <kti...@redhat.com>
>
> * fold-const.c (fold_range_test): Add
> support for one-bit bitwise operations.
> (fold_truthop): Likewise.
>
> 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 08:07:59.000000000 +0200
> +++ gcc/gcc/fold-const.c 2011-07-13 08:59:26.117620200 +0200
> @@ -4819,7 +4819,8 @@ fold_range_test (location_t loc, enum tr
> tree op0, tree op1)
> {
> int or_op = (code == TRUTH_ORIF_EXPR
> - || code == TRUTH_OR_EXPR);
> + || code == TRUTH_OR_EXPR
> + || code == BIT_IOR_EXPR);
> int in0_p, in1_p, in_p;
> tree low0, low1, low, high0, high1, high;
> bool strict_overflow_p = false;
> @@ -4890,7 +4891,7 @@ fold_range_test (location_t loc, enum tr
> }
> }
>
> - return 0;
> + return NULL_TREE;
> }
>
> /* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
> @@ -5118,8 +5119,9 @@ fold_truthop (location_t loc, enum tree_
> }
> }
>
> - code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
> - ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
> + if (code != BIT_AND_EXPR && code != BIT_IOR_EXPR)
> + code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
> + ? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
>
> /* If the RHS can be evaluated unconditionally and its operands are
> simple, it wins to evaluate the RHS unconditionally on machines
> @@ -5134,7 +5136,7 @@ fold_truthop (location_t loc, enum tree_
> && simple_operand_p (rr_arg))
> {
> /* Convert (a != 0) || (b != 0) into (a | b) != 0. */
> - if (code == TRUTH_OR_EXPR
> + if ((code == TRUTH_OR_EXPR || code == BIT_IOR_EXPR)
> && lcode == NE_EXPR && integer_zerop (lr_arg)
> && rcode == NE_EXPR && integer_zerop (rr_arg)
> && TREE_TYPE (ll_arg) == TREE_TYPE (rl_arg)
> @@ -5145,7 +5147,7 @@ fold_truthop (location_t loc, enum tree_
> build_int_cst (TREE_TYPE (ll_arg), 0));
>
> /* Convert (a == 0) && (b == 0) into (a | b) == 0. */
> - if (code == TRUTH_AND_EXPR
> + if ((code == TRUTH_AND_EXPR || code == BIT_AND_EXPR)
> && lcode == EQ_EXPR && integer_zerop (lr_arg)
> && rcode == EQ_EXPR && integer_zerop (rr_arg)
> && TREE_TYPE (ll_arg) == TREE_TYPE (rl_arg)
> @@ -5209,7 +5211,8 @@ fold_truthop (location_t loc, enum tree_
> fail. However, we can convert a one-bit comparison against zero into
> the opposite comparison against that bit being set in the field. */
>
> - wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
> + wanted_code = ((code == TRUTH_AND_EXPR
> + || code == BIT_AND_EXPR) ? EQ_EXPR : NE_EXPR);
> if (lcode != wanted_code)
> {
> if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
>
