[llvm] AMDGPU: Return legal addressmode correctly for flat scratch (PR #71494)

[Jay Foad via llvm-commits]

================
@@ -1357,6 +1357,13 @@ bool SITargetLowering::isLegalGlobalAddressingMode(const AddrMode &AM) const {
   return isLegalMUBUFAddressingMode(AM);
 }
 
+bool SITargetLowering::isLegalFlatScratchAddressingMode(
----------------
jayfoad wrote:

As an alternative, you could change `isLegalFlatAddressingMode` to take `AS` and `Variant` as arguments.

https://github.com/llvm/llvm-project/pull/71494