[llvm-branch-commits] [llvm] [LoongArch] Fold selects sharing operands with binary operations (PR #215520)

[via llvm-branch-commits]

heiher wrote:

> `select-binop-combine.ll` already performs a similar transformation at the IR level. After running `opt -O2`, the resulting code has the same effect as this combine. Do we still need to handle this separately in the backend?

Thanks! I checked the assembly generated by `clang -O3` when building the llvm-test-suite, and the expected codegen improvement is present with this patch. So I think this backend combine complements the existing IR-level optimization?

https://gitlab.com/la-rs/llvm-opt-ci/-/commit/1f2459e50ac1922777319b3b6b645cc55dd40e9f?view=parallel

https://github.com/llvm/llvm-project/pull/215520