Hello,

this patch implements the X op !X patterns within tree-ssa-forwprop.c without using here const-fold routines.  Additionally it does some trivial folding for X op X.  Implementation
also looks through [(type)] X op [(type)] !X, if type of X is integral and precision is suitable
for operation.

ChangeLog gcc/

2011-06-28  Kai Tietz  <ktietz@redhat.com>

        * tree-ssa-forwprop.c (operand_precision_onep): New
        function.
        (find_possible_not_expr_argument): Likewise.
        (simplify_bitwise_binary_1): Likewise.
        (simplify_bitwise_binary): Use simplify_bitwise_binary_1
        for detecting various X op !X optimizations.

ChangeLog gcc/testsuite

2011-06-28  Kai Tietz  <ktietz@redhat.com>

        * gcc.dg/binop-notand1a.c: New test.
        * gcc.dg/binop-notand2a.c: New test.
        * gcc.dg/binop-notand3a.c: New test.
        * gcc.dg/binop-notand4a.c: New test.
        * gcc.dg/binop-notand5a.c: New test.
        * gcc.dg/binop-notand6a.c: New test.
        * gcc.dg/binop-notor1.c: New test.
        * gcc.dg/binop-notor2.c: New test.
        * gcc.dg/binop-notxor1.c: New test.
        * gcc.dg/binop-notxor2.c: New test.

Bootstrapped and regression tested for all languages plus Ada and Obj-C for x86_64-pc-linux-gnu. Ok for apply?

Regards,
Kai