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

[via llvm-commits]

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@@ -1146,10 +1146,23 @@ bool AMDGPUDAGToDAGISel::isDSOffset2Legal(SDValue Base, unsigned Offset0,
   return CurDAG->SignBitIsZero(Base);
 }
 
-bool AMDGPUDAGToDAGISel::isFlatScratchBaseLegal(SDValue Base,
+bool AMDGPUDAGToDAGISel::isFlatScratchBaseLegal(SDValue Addr, SDValue Base,
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ruiling wrote:

I have added the check for two ADDs, and refine the code to be more reasonable. Please help take a look. Thanks!

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