[llvm] [GlobalIsel] Combine zext of trunc (episode II) (PR #108305)

[Thorsten Schütt via llvm-commits]

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@@ -2524,20 +2524,6 @@ bool CombinerHelper::matchCombineAnyExtTrunc(MachineInstr &MI, Register &Reg) {
                   m_GTrunc(m_all_of(m_Reg(Reg), m_SpecificType(DstTy))));
 }
 
-bool CombinerHelper::matchCombineZextTrunc(MachineInstr &MI, Register &Reg) {
-  assert(MI.getOpcode() == TargetOpcode::G_ZEXT && "Expected a G_ZEXT");
-  Register DstReg = MI.getOperand(0).getReg();
-  Register SrcReg = MI.getOperand(1).getReg();
-  LLT DstTy = MRI.getType(DstReg);
-  if (mi_match(SrcReg, MRI,
-               m_GTrunc(m_all_of(m_Reg(Reg), m_SpecificType(DstTy))))) {
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tschuett wrote:

Here is the test in episode I of this combine.

https://github.com/llvm/llvm-project/pull/108305