[llvm-branch-commits] [llvm] [AMDGPU] Use reverse iteration in CodeGenPrepare (PR #145484)

[Jay Foad via llvm-branch-commits]

jayfoad wrote:

> This is not a simplifying pass, it is making the IR more complicated. We have to do hacks like this to prevent later more profitable combines from needing to parse out expanded IR:

Fair enough, makes sense. I just want to make sure the justification is properly understood and explained, preferably in the commit message.

> https://github.com/llvm/llvm-project/blob/fa5d7c926f5f571397eb1981649198136f1d6a92/llvm/lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp#L2332

I only disagree with the "like a normal combiner" part of that comment :)

https://github.com/llvm/llvm-project/pull/145484