[llvm-branch-commits] [llvm] [AMDGPU] Move S_BFE lowering into RegBankCombiner (PR #141589)

[Shilei Tian via llvm-branch-commits]

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@@ -392,6 +394,55 @@ void AMDGPURegBankCombinerImpl::applyCanonicalizeZextShiftAmt(
   MI.eraseFromParent();
 }
 
+bool AMDGPURegBankCombinerImpl::lowerUniformBFX(MachineInstr &MI) const {
+  assert(MI.getOpcode() == TargetOpcode::G_UBFX ||
+         MI.getOpcode() == TargetOpcode::G_SBFX);
+  const bool Signed = (MI.getOpcode() == TargetOpcode::G_SBFX);
+
+  Register DstReg = MI.getOperand(0).getReg();
+  const RegisterBank *RB = RBI.getRegBank(DstReg, MRI, TRI);
+  assert(RB && "No RB?");
+  if (RB->getID() != AMDGPU::SGPRRegBankID)
+    return false;
+
+  Register SrcReg = MI.getOperand(1).getReg();
+  Register OffsetReg = MI.getOperand(2).getReg();
+  Register WidthReg = MI.getOperand(3).getReg();
+
+  const LLT S32 = LLT::scalar(32);
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shiltian wrote:

Is it necessary to use `const` local scalar variable?

https://github.com/llvm/llvm-project/pull/141589