[libclc] [libclc] Reduce bithacking in CLC frexp (PR #129871)

[Fraser Cormack via cfe-commits]

frasercrmck wrote:

That's interesting. As I said alive2 was happy with the before/after IR diff of the AMDGPU version of this builtin. Do you know what might be going on? Is that the fp64 or fp32 test that's failing?

https://github.com/llvm/llvm-project/pull/129871