[llvm-branch-commits] [llvm] [AMDGPU] Add sext_trunc in RegBankCombiner (PR #131623)

[Pierre van Houtryve via llvm-branch-commits]

Pierre-vh wrote:

Ah, this doesn't do anything at this stage. It's only helpful once we disable widening of i16 ops to i32 in CGP. Then this pattern can appear and it'll fold it.

This combine is tested in AArch64. Should I copy over a few simple test cases in the AMDGPU folder just to show the combine works in RegBankCombiner?

https://github.com/llvm/llvm-project/pull/131623