https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109505
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
/* (X & Y) & Y -> X & Y
(X | Y) | Y -> X | Y */
(for op (bit_and bit_ior)
(simplify
(op:c (convert1?@2 (op:c @0 @@1)) (convert2? @1))
@2))
...
/* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
operands are another bit-wise operation with a common input. If so,
distribute the bit operations to save an operation and possibly two if
constants are involved. For example, convert
(A | B) & (A | C) into A | (B & C)
Further simplification will occur if B and C are constants. */
(for op (bit_and bit_ior bit_xor)
rop (bit_ior bit_and bit_and)
(simplify
(op (convert? (rop:c @@0 @1)) (convert? (rop:c @0 @2)))
(if (tree_nop_conversion_p (type, TREE_TYPE (@1))
&& tree_nop_conversion_p (type, TREE_TYPE (@2)))
(rop (convert @0) (op (convert @1) (convert @2))))))
...
/* (x | CST1) & CST2 -> (x & CST2) | (CST1 & CST2) */
(simplify
(bit_and (bit_ior @0 CONSTANT_CLASS_P@1) CONSTANT_CLASS_P@2)
(bit_ior (bit_and @0 @2) (bit_and @1 @2)))
