[llvm] SimplifyLibCalls: Don't require ldexp to emit intrinsic in exp2 combine (PR #92707)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> On Windows specifically, we have ldexp; the issue is just that we don't have ldexpf.

Can we handle this by just promoting float to double in codegen? 

https://github.com/llvm/llvm-project/pull/92707