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

[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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vangthao95 wrote:

Sorry, I mean in the case where it is attempting to select both an SOffset and Offset (Immediate). It will first attempt to select the immediate Offset then the SOffset. When selecting for SOffset, the Offset pointer is not passed in so when selecting SOffset, it has no knowledge of the immediate Offset value.

nullptr is passed for Offset here: https://github.com/llvm/llvm-project/blob/main/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp#L2082

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