[llvm] [X86][GlobalIsel] G_BITCAST support (PR #144473)

[via llvm-commits]

mahesh-attarde wrote:

> > @mahesh-attarde could you please elaborate why this change is needed because the tests pass without this PR: https://godbolt.org/z/EEzP4nn4n
> > There is a problem with double conversions in `test2` on `i686` but it is all over there.
> 
> While doing FP class test we need to convert F32 to I32 and F64 to I64 and create sequence of bitwise ops.

https://github.com/mahesh-attarde/llvm-project/pull/4/files#diff-67fe52af4babc3c78a4ad94f25bc84a724cd6a4aacefd6db24887d5d29c3b936R797

https://github.com/llvm/llvm-project/pull/144473