[llvm] [X86] Compute `CTLZ` using fp math for `v4i32` on SSE2 targets (PR #190930)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

@def3r Did you take a look at https://stackoverflow.com/a/58827596? Simplifying that AVX2 code should work in general without any type extension for vXi32 types, for x86 at least.

https://github.com/llvm/llvm-project/pull/190930