[llvm] [AMDGPU][GlobalIsel] Add RegBankLegalize rules and lowering for G_AMDGPU_S_BUFFER_LOAD (PR #192480)

[Matt Arsenault via llvm-commits]

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@@ -300,6 +300,73 @@ bool RegBankLegalizeHelper::executeInWaterfallLoop(MachineIRBuilder &B,
   return true;
 }
 
+// Analyze a combined offset from an llvm.amdgcn.s.buffer intrinsic and store
+// the three offsets (voffset, soffset and instoffset)
+unsigned RegBankLegalizeHelper::setBufferOffsets(
+    MachineIRBuilder &B, Register CombinedOffset, Register &VOffsetReg,
+    Register &SOffsetReg, int64_t &InstOffsetVal, Align Alignment) {
+  const GCNSubtarget &ST = B.getMF().getSubtarget<GCNSubtarget>();
+  const SIInstrInfo &TII = *ST.getInstrInfo();
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arsenm wrote:

These should be members of the class 

https://github.com/llvm/llvm-project/pull/192480