[Bug tree-optimization/106138] Inefficient code generation: logical AND of disjoint booleans from equal and bitwise AND not optimized to constant false

[peter at cordes dot ca via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106138

Peter Cordes <peter at cordes dot ca> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |peter at cordes dot ca

--- Comment #3 from Peter Cordes <peter at cordes dot ca> ---
Ideally, bitwise & of booleans should also be handled, not just &&.
A testcase (https://godbolt.org/z/qvosv8q7c) makes it easy to check both.

//#define LOGIC_AND 
_Bool f2(char x)
{
    _Bool b1 = x == 2;
    _Bool b2 = x & 1;

    #ifdef LOGIC_AND
      return b1 && b2;
    #else
      return b1 & b2;
    #endif
}

(Clang optimized it to return false for the && version, but not bitwise.  GCC
currently doesn't optimize either way.)
This was originally posted on Stack Overflow
(https://stackoverflow.com/q/72802469/224132), BTW.