[clang] [compiler-rt] [llvm] [TargetLowering] Set the default `getCmpLibcallReturnType` to word size (PR #192441)

[Trevor Gross via cfe-commits]

tgross35 wrote:

For PPC: @amy-kwan @lei137
For RISCV: @asb @topperc
For x86: @RKSimon @phoebewang

As far as I can tell the codegen changes here are just access and comparison sizes on 64-bit targets which should have no real impact. (I believe any targets where this is more expensive are already overridden both in LLVM and GCC).

https://github.com/llvm/llvm-project/pull/192441