[InstCombine] !a == (a < 0) is not optimized

[k-arrows]

Consider the following functions:

int foo(int a)
{
   return !a == (a > 0);
}

int bar(int a)
{
   return (a < 0);
}

int baz(int a)
{
   return !a == (a < 0);
}

int qux(int a)
{
   return (a > 0);
}

Both Clang and GCC can optimize foo to bar. GCC can also optimize baz to qux, but Clang cannot.
https://godbolt.org/z/exvTE8Gn7
https://alive2.llvm.org/ce/z/LGvASc

[XChy]

The fold zext(icmp (A, xxx)) == shr(A, BW - 1) => not(trunc(xor(zext(icmp), shl))) would be a more convenient way to optimize it.
alive-tv