[PATCH] D155051: [AMDGPU] Add sanity check that fixes bad shift operation in AMD backend

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/SILoadStoreOptimizer.cpp:877
+
   unsigned AllowedBitsForMin = llvm::countr_zero(MaxMask);
   if ((1u << AllowedBitsForMin) <= MinMask)
----------------
First I'd say countr_zero is just broken if this is UB.

Also needs testcase


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D155051/new/

https://reviews.llvm.org/D155051