[llvm] [BranchFolding][RISCV] Optimize branches NE/EQ to zero or one (PR #131684)

[Mikhail R. Gadelha via llvm-commits]

https://github.com/mikhailramalho commented:

Nice work! It's great to see this finally fixed.

Just one question: have you consider implementing this in `RISCVInstrInfo::optimizeCondBranch`? 

It's only used here:
https://github.com/llvm/llvm-project/blob/4f7dc99a8a3e34e925ef66e7069b01b811e837ba/llvm/lib/CodeGen/PeepholeOptimizer.cpp#L1793

but I wonder if we could get more cases covered by changing `optimizeCondBranch` 
(instead of the new `trySimplifyCondBr`) + your changes to `RISCVInstrInfo::analyzeBranch`.

I'll run SPEC with your patch tonight, we should have the results tomorrow morning

https://github.com/llvm/llvm-project/pull/131684