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[CodeGen] Minor refactor of CSRSavedLocation struct [nfc] #170721

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Merged
preames merged 1 commit into from
Dec 4, 2025
Merged

[CodeGen] Minor refactor of CSRSavedLocation struct [nfc] #170721

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25 changes: 18 additions & 7 deletions llvm/lib/CodeGen/CFIInstrInserter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -90,9 +90,20 @@ class CFIInstrInserter : public MachineFunctionPass {
/// contains the location where CSR register is saved.
struct CSRSavedLocation {
CSRSavedLocation(std::optional<unsigned> R, std::optional<int> O)
: Reg(R), Offset(O) {}
: Reg(R), Offset(O) {
assert((Reg.has_value() ^ Offset.has_value()) &&
"Register and offset can not both be valid");
}
std::optional<unsigned> Reg;
std::optional<int> Offset;

bool operator==(const CSRSavedLocation &RHS) const {
return Reg == RHS.Reg && Offset == RHS.Offset;
}

bool operator!=(const CSRSavedLocation &RHS) const {
return !(*this == RHS);
}
};

/// Contains cfa offset and register values valid at entry and exit of basic
Expand Down Expand Up @@ -267,11 +278,11 @@ void CFIInstrInserter::calculateOutgoingCFAInfo(MBBCFAInfo &MBBInfo) {
break;
}
if (CSRReg || CSROffset) {
CSRSavedLocation Loc(CSRReg, CSROffset);
auto It = CSRLocMap.find(CFI.getRegister());
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@topperc topperc Dec 4, 2025

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We should try the insert instead of find here. If the insert fails, do the check to make sure the value we tried to insert matches what was already there.

This can be a follow up.

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@preames preames Dec 4, 2025

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See #170760

if (It == CSRLocMap.end()) {
CSRLocMap.insert(
{CFI.getRegister(), CSRSavedLocation(CSRReg, CSROffset)});
} else if (It->second.Reg != CSRReg || It->second.Offset != CSROffset) {
CSRLocMap.insert({CFI.getRegister(), Loc});
} else if (It->second != Loc) {
reportFatalInternalError(
"Different saved locations for the same CSR");
}
Expand Down Expand Up @@ -397,11 +408,11 @@ bool CFIInstrInserter::insertCFIInstrs(MachineFunction &MF) {
if (!RO.Reg && RO.Offset) {
CFIIndex = MF.addFrameInst(
MCCFIInstruction::createOffset(nullptr, Reg, *RO.Offset));
} else if (RO.Reg && !RO.Offset) {
} else {
assert((RO.Reg && !RO.Offset) &&
"Reg and Offset cannot both be valid/invalid");
CFIIndex = MF.addFrameInst(
MCCFIInstruction::createRegister(nullptr, Reg, *RO.Reg));
} else {
llvm_unreachable("RO.Reg and RO.Offset cannot both be valid/invalid");
}
BuildMI(*MBBInfo.MBB, MBBI, DL, TII->get(TargetOpcode::CFI_INSTRUCTION))
.addCFIIndex(CFIIndex);
Expand Down
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