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[AArch64] Avoid hardcoding spill size/align in FrameLowering (NFC) #123080

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Jan 17, 2025
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69 changes: 20 additions & 49 deletions llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -2926,26 +2926,12 @@ struct RegPairInfo {
int FrameIdx;
int Offset;
enum RegType { GPR, FPR64, FPR128, PPR, ZPR, VG } Type;
const TargetRegisterClass *RC;

RegPairInfo() = default;

bool isPaired() const { return Reg2 != AArch64::NoRegister; }

unsigned getScale() const {
switch (Type) {
case PPR:
return 2;
case GPR:
case FPR64:
case VG:
return 8;
case ZPR:
case FPR128:
return 16;
}
llvm_unreachable("Unsupported type");
}

bool isScalable() const { return Type == PPR || Type == ZPR; }
};

Expand Down Expand Up @@ -3023,20 +3009,27 @@ static void computeCalleeSaveRegisterPairs(
RegPairInfo RPI;
RPI.Reg1 = CSI[i].getReg();

if (AArch64::GPR64RegClass.contains(RPI.Reg1))
if (AArch64::GPR64RegClass.contains(RPI.Reg1)) {
RPI.Type = RegPairInfo::GPR;
else if (AArch64::FPR64RegClass.contains(RPI.Reg1))
RPI.RC = &AArch64::GPR64RegClass;
} else if (AArch64::FPR64RegClass.contains(RPI.Reg1)) {
RPI.Type = RegPairInfo::FPR64;
else if (AArch64::FPR128RegClass.contains(RPI.Reg1))
RPI.RC = &AArch64::FPR64RegClass;
} else if (AArch64::FPR128RegClass.contains(RPI.Reg1)) {
RPI.Type = RegPairInfo::FPR128;
else if (AArch64::ZPRRegClass.contains(RPI.Reg1))
RPI.RC = &AArch64::FPR128RegClass;
} else if (AArch64::ZPRRegClass.contains(RPI.Reg1)) {
RPI.Type = RegPairInfo::ZPR;
else if (AArch64::PPRRegClass.contains(RPI.Reg1))
RPI.RC = &AArch64::ZPRRegClass;
} else if (AArch64::PPRRegClass.contains(RPI.Reg1)) {
RPI.Type = RegPairInfo::PPR;
else if (RPI.Reg1 == AArch64::VG)
RPI.RC = &AArch64::PPRRegClass;
} else if (RPI.Reg1 == AArch64::VG) {
RPI.Type = RegPairInfo::VG;
else
RPI.RC = &AArch64::FIXED_REGSRegClass;
} else {
llvm_unreachable("Unsupported register class.");
}

// Add the stack hazard size as we transition from GPR->FPR CSRs.
if (AFI->hasStackHazardSlotIndex() &&
Expand All @@ -3045,7 +3038,7 @@ static void computeCalleeSaveRegisterPairs(
ByteOffset += StackFillDir * StackHazardSize;
LastReg = RPI.Reg1;

int Scale = RPI.getScale();
int Scale = TRI->getSpillSize(*RPI.RC);
// Add the next reg to the pair if it is in the same register class.
if (unsigned(i + RegInc) < Count && !AFI->hasStackHazardSlotIndex()) {
Register NextReg = CSI[i + RegInc].getReg();
Expand Down Expand Up @@ -3254,38 +3247,26 @@ bool AArch64FrameLowering::spillCalleeSavedRegisters(
// Rationale: This sequence saves uop updates compared to a sequence of
// pre-increment spills like stp xi,xj,[sp,#-16]!
// Note: Similar rationale and sequence for restores in epilog.
unsigned Size;
Align Alignment;
unsigned Size = TRI->getSpillSize(*RPI.RC);
Align Alignment = TRI->getSpillAlign(*RPI.RC);
switch (RPI.Type) {
case RegPairInfo::GPR:
StrOpc = RPI.isPaired() ? AArch64::STPXi : AArch64::STRXui;
Size = 8;
Alignment = Align(8);
break;
case RegPairInfo::FPR64:
StrOpc = RPI.isPaired() ? AArch64::STPDi : AArch64::STRDui;
Size = 8;
Alignment = Align(8);
break;
case RegPairInfo::FPR128:
StrOpc = RPI.isPaired() ? AArch64::STPQi : AArch64::STRQui;
Size = 16;
Alignment = Align(16);
break;
case RegPairInfo::ZPR:
StrOpc = RPI.isPaired() ? AArch64::ST1B_2Z_IMM : AArch64::STR_ZXI;
Size = 16;
Alignment = Align(16);
break;
case RegPairInfo::PPR:
StrOpc = AArch64::STR_PXI;
Size = 2;
Alignment = Align(2);
break;
case RegPairInfo::VG:
StrOpc = AArch64::STRXui;
Size = 8;
Alignment = Align(8);
break;
}

Expand Down Expand Up @@ -3495,33 +3476,23 @@ bool AArch64FrameLowering::restoreCalleeSavedRegisters(
// ldp x22, x21, [sp, #0] // addImm(+0)
// Note: see comment in spillCalleeSavedRegisters()
unsigned LdrOpc;
unsigned Size;
Align Alignment;
unsigned Size = TRI->getSpillSize(*RPI.RC);
Align Alignment = TRI->getSpillAlign(*RPI.RC);
switch (RPI.Type) {
case RegPairInfo::GPR:
LdrOpc = RPI.isPaired() ? AArch64::LDPXi : AArch64::LDRXui;
Size = 8;
Alignment = Align(8);
break;
case RegPairInfo::FPR64:
LdrOpc = RPI.isPaired() ? AArch64::LDPDi : AArch64::LDRDui;
Size = 8;
Alignment = Align(8);
break;
case RegPairInfo::FPR128:
LdrOpc = RPI.isPaired() ? AArch64::LDPQi : AArch64::LDRQui;
Size = 16;
Alignment = Align(16);
break;
case RegPairInfo::ZPR:
LdrOpc = RPI.isPaired() ? AArch64::LD1B_2Z_IMM : AArch64::LDR_ZXI;
Size = 16;
Alignment = Align(16);
break;
case RegPairInfo::PPR:
LdrOpc = AArch64::LDR_PXI;
Size = 2;
Alignment = Align(2);
break;
case RegPairInfo::VG:
continue;
Expand Down
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