[llvm] [AMDGPU] Fix negative immediate offset for unbuffered smem loads (PR #89165)

[Matt Arsenault via llvm-commits]

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@@ -1985,35 +1985,47 @@ bool AMDGPUDAGToDAGISel::SelectScratchSVAddr(SDNode *N, SDValue Addr,
 // offsets available on CI.
 bool AMDGPUDAGToDAGISel::SelectSMRDOffset(SDValue ByteOffsetNode,
                                           SDValue *SOffset, SDValue *Offset,
-                                          bool Imm32Only, bool IsBuffer) const {
+                                          bool Imm32Only, bool IsBuffer,
+                                          bool HasSOffset,
+                                          int64_t ImmOffset) const {
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arsenm wrote:

The offset is already passed in, having a second copy of it in the immediate case is harder to follow 

https://github.com/llvm/llvm-project/pull/89165