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[Mips] Add support of MipsInstrInfo::getNop() #139863

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Merged
merged 1 commit into from
May 14, 2025
Merged

[Mips] Add support of MipsInstrInfo::getNop() #139863

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8 changes: 8 additions & 0 deletions llvm/lib/Target/Mips/MipsInstrInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/MC/MCInstBuilder.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/Target/TargetMachine.h"
#include <cassert>
Expand Down Expand Up @@ -53,6 +54,13 @@ bool MipsInstrInfo::isZeroImm(const MachineOperand &op) const {
return op.isImm() && op.getImm() == 0;
}

MCInst MipsInstrInfo::getNop() const {
return MCInstBuilder(Mips::SLL)
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Maybe we should try to support micromips?

.addReg(Mips::ZERO)
.addReg(Mips::ZERO)
.addImm(0);
}

/// insertNoop - If data hazard condition is found insert the target nop
/// instruction.
void MipsInstrInfo::
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2 changes: 2 additions & 0 deletions llvm/lib/Target/Mips/MipsInstrInfo.h
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Expand Up @@ -57,6 +57,8 @@ class MipsInstrInfo : public MipsGenInstrInfo {

explicit MipsInstrInfo(const MipsSubtarget &STI, unsigned UncondBrOpc);

MCInst getNop() const override;

static const MipsInstrInfo *create(MipsSubtarget &STI);

/// Branch Analysis
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13 changes: 13 additions & 0 deletions llvm/test/CodeGen/Mips/unreachable.ll
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@@ -0,0 +1,13 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
; RUN: llc -mtriple=mipsel-windows-gnu < %s | FileCheck %s -check-prefix=MIPSEL

define void @unreachable() {
; MIPSEL-LABEL: unreachable:
; MIPSEL: # %bb.0: # %entry
; MIPSEL-NEXT: .insn
; MIPSEL-NEXT: nop

entry:
unreachable
}