https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110111
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
f1:
_6 = b_2(D) ^ c_3(D);
_7 = a_1(D) & _6;
_4 = c_3(D) ^ _7;
Which was done due to:
/* (x & ~m) | (y & m) -> ((x ^ y) & m) ^ x */
(simplify
(bit_ior:c (bit_and:cs @0 (bit_not @2)) (bit_and:cs @1 @2))
(bit_xor (bit_and (bit_xor @0 @1) @2) @0))
Note if we move this over to bitwise_inverted_equal_p (which we should), we
will lose also:
```
bool f(int a, int b, int t)
{
bool x = a == 0;
bool y = b == 1;
bool m = t == 2;
bool mp = !m;
return (x & mp) | (y & m);
}
```
Which is currently handled.
We should check for `element_precision (type) == 1` too.
So something like:
(simplify
(bit_ior (bit_and:c@and1 @0 @3) (bit_and:c@and2 @1 @2))
(with { bool wascmp; }
(if (bitwise_inverted_equal_p (@0, @2, wascmp))
(switch
/* For 1bit, wascmp can be true and we can just convert it into `m ? y : x`
*/
(if (INTEGRAL_TYPE_P (type) && element_precision (type) == 1)
(cond @3 @0 @1))
(if (!wascmp && element_precision (type) != 1
&& single_use (@and1) && single_use (@and2))
(bit_xor (bit_and (bit_xor @0 @1) @2) @0))
)
)
)
)
)
/* 1bit `((x ^ y) & m) ^ x` should just be convert into `m ? y : x` early */
(simplify
(bit_xor:c (bit_and:c (bit_xor:c @0 @1) @2) @0)
(if (INTEGRAL_TYPE_P (type) && element_precision (type) == 1)
(cond @2 @0 @1)))
