[llvm] [AMDGPU] Folding imm offset in more cases for scratch access (PR #70634)

[via llvm-commits]

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@@ -1886,7 +1899,8 @@ bool AMDGPUDAGToDAGISel::SelectScratchSVAddr(SDNode *N, SDValue Addr,
     return false;
   }
 
-  if (!isFlatScratchBaseLegal(SAddr) || !isFlatScratchBaseLegal(VAddr))
+  if (!isFlatScratchBaseLegal(Addr, SAddr) ||
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ruiling wrote:

@petar-avramovic should probably know about some details as the logic was introduced by him.

https://github.com/llvm/llvm-project/pull/70634