https://github.com/arsenm created
https://github.com/llvm/llvm-project/pull/140608
We weren't fully respecting the type of a def of an immediate vs.
the type at the use point. Refactor the folding logic to track the
value to fold, as well as a subregister to apply to the underlying
value. This is similar to how PeepholeOpt tracks subregisters (though
only for pure copy-like instructions, no constants).
Fixes #139317
>From 045021f4ed97861a352e9ebd43e1f1049021e987 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <matthew.arsena...@amd.com>
Date: Thu, 15 May 2025 10:51:39 +0200
Subject: [PATCH] AMDGPU: Fix tracking subreg defs when folding through
reg_sequence
We weren't fully respecting the type of a def of an immediate vs.
the type at the use point. Refactor the folding logic to track the
value to fold, as well as a subregister to apply to the underlying
value. This is similar to how PeepholeOpt tracks subregisters (though
only for pure copy-like instructions, no constants).
Fixes #139317
---
llvm/lib/Target/AMDGPU/SIFoldOperands.cpp | 406 +++++++++++-------
...issue139317-bad-opsel-reg-sequence-fold.ll | 3 +-
.../si-fold-operands-subreg-imm.gfx942.mir | 8 +-
.../AMDGPU/si-fold-operands-subreg-imm.mir | 4 +-
4 files changed, 250 insertions(+), 171 deletions(-)
diff --git a/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
b/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
index 9bbc8e75fd31b..eb7fb94e25f5c 100644
--- a/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
+++ b/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
@@ -25,52 +25,151 @@ using namespace llvm;
namespace {
-struct FoldCandidate {
- MachineInstr *UseMI;
+/// Track a value we may want to fold into downstream users, applying
+/// subregister extracts along the way.
+struct FoldableDef {
union {
- MachineOperand *OpToFold;
+ MachineOperand *OpToFold = nullptr;
uint64_t ImmToFold;
int FrameIndexToFold;
};
- int ShrinkOpcode;
- unsigned UseOpNo;
+
+ /// Register class of the originally defined value.
+ const TargetRegisterClass *DefRC = nullptr;
+
+ /// Track the original defining instruction for the value.
+ const MachineInstr *DefMI = nullptr;
+
+ /// Subregister to apply to the value at the use point.
+ unsigned DefSubReg = AMDGPU::NoSubRegister;
+
+ /// Kind of value stored in the union.
MachineOperand::MachineOperandType Kind;
- bool Commuted;
- FoldCandidate(MachineInstr *MI, unsigned OpNo, MachineOperand *FoldOp,
- bool Commuted_ = false,
- int ShrinkOp = -1) :
- UseMI(MI), OpToFold(nullptr), ShrinkOpcode(ShrinkOp), UseOpNo(OpNo),
- Kind(FoldOp->getType()),
- Commuted(Commuted_) {
- if (FoldOp->isImm()) {
- ImmToFold = FoldOp->getImm();
- } else if (FoldOp->isFI()) {
- FrameIndexToFold = FoldOp->getIndex();
+ FoldableDef() = delete;
+ FoldableDef(MachineOperand &FoldOp, const TargetRegisterClass *DefRC,
+ unsigned DefSubReg = AMDGPU::NoSubRegister)
+ : DefRC(DefRC), DefSubReg(DefSubReg), Kind(FoldOp.getType()) {
+
+ if (FoldOp.isImm()) {
+ ImmToFold = FoldOp.getImm();
+ } else if (FoldOp.isFI()) {
+ FrameIndexToFold = FoldOp.getIndex();
} else {
- assert(FoldOp->isReg() || FoldOp->isGlobal());
- OpToFold = FoldOp;
+ assert(FoldOp.isReg() || FoldOp.isGlobal());
+ OpToFold = &FoldOp;
}
+
+ DefMI = FoldOp.getParent();
}
- FoldCandidate(MachineInstr *MI, unsigned OpNo, int64_t FoldImm,
- bool Commuted_ = false, int ShrinkOp = -1)
- : UseMI(MI), ImmToFold(FoldImm), ShrinkOpcode(ShrinkOp), UseOpNo(OpNo),
- Kind(MachineOperand::MO_Immediate), Commuted(Commuted_) {}
+ FoldableDef(int64_t FoldImm, const TargetRegisterClass *DefRC,
+ unsigned DefSubReg = AMDGPU::NoSubRegister)
+ : ImmToFold(FoldImm), DefRC(DefRC), DefSubReg(DefSubReg),
+ Kind(MachineOperand::MO_Immediate) {}
+
+ /// Copy the current def and apply \p SubReg to the value.
+ FoldableDef getWithSubReg(const SIRegisterInfo &TRI, unsigned SubReg) const {
+ FoldableDef Copy(*this);
+ Copy.DefSubReg = TRI.composeSubRegIndices(DefSubReg, SubReg);
+ return Copy;
+ }
+
+ bool isReg() const { return Kind == MachineOperand::MO_Register; }
+
+ Register getReg() const {
+ assert(isReg());
+ return OpToFold->getReg();
+ }
+
+ unsigned getSubReg() const {
+ assert(isReg());
+ return OpToFold->getSubReg();
+ }
+
+ bool isImm() const { return Kind == MachineOperand::MO_Immediate; }
bool isFI() const {
return Kind == MachineOperand::MO_FrameIndex;
}
- bool isImm() const {
- return Kind == MachineOperand::MO_Immediate;
+ int getFI() const {
+ assert(isFI());
+ return FrameIndexToFold;
}
- bool isReg() const {
- return Kind == MachineOperand::MO_Register;
+ bool isGlobal() const { return OpToFold->isGlobal(); }
+
+ /// Return the effective immediate value defined by this instruction, after
+ /// application of any subregister extracts which may exist between the use
+ /// and def instruction.
+ std::optional<int64_t> getEffectiveImmVal() const {
+ assert(isImm());
+ return SIInstrInfo::extractSubregFromImm(ImmToFold, DefSubReg);
}
- bool isGlobal() const { return Kind == MachineOperand::MO_GlobalAddress; }
+ /// Check if it is legal to fold this effective value into \p MI's \p OpNo
+ /// operand.
+ bool isOperandLegal(const SIInstrInfo &TII, const MachineInstr &MI,
+ unsigned OpIdx) const {
+ switch (Kind) {
+ case MachineOperand::MO_Immediate: {
+ std::optional<int64_t> ImmToFold = getEffectiveImmVal();
+ if (!ImmToFold)
+ return false;
+
+ // TODO: Should verify the subregister index is supported by the class
+ // TODO: Avoid the temporary MachineOperand
+ MachineOperand TmpOp = MachineOperand::CreateImm(*ImmToFold);
+ return TII.isOperandLegal(MI, OpIdx, &TmpOp);
+ }
+ case MachineOperand::MO_FrameIndex: {
+ if (DefSubReg != AMDGPU::NoSubRegister)
+ return false;
+ MachineOperand TmpOp = MachineOperand::CreateFI(FrameIndexToFold);
+ return TII.isOperandLegal(MI, OpIdx, &TmpOp);
+ }
+ default:
+ // TODO: Try to apply DefSubReg, for global address we can extract
+ // low/high.
+ if (DefSubReg != AMDGPU::NoSubRegister)
+ return false;
+ return TII.isOperandLegal(MI, OpIdx, OpToFold);
+ }
+
+ llvm_unreachable("covered MachineOperand kind switch");
+ }
+};
+
+struct FoldCandidate {
+ MachineInstr *UseMI;
+ FoldableDef Def;
+ int ShrinkOpcode;
+ unsigned UseOpNo;
+ bool Commuted;
+
+ FoldCandidate(MachineInstr *MI, unsigned OpNo, FoldableDef Def,
+ bool Commuted_ = false, int ShrinkOp = -1)
+ : UseMI(MI), Def(Def), ShrinkOpcode(ShrinkOp), UseOpNo(OpNo),
+ Commuted(Commuted_) {}
+
+ bool isFI() const { return Def.Kind == MachineOperand::MO_FrameIndex; }
+
+ int getFI() const {
+ assert(isFI());
+ return Def.FrameIndexToFold;
+ }
+
+ bool isImm() const { return Def.isImm(); }
+
+ bool isReg() const { return Def.isReg(); }
+
+ Register getReg() const {
+ assert(isReg());
+ return Def.OpToFold->getReg();
+ }
+
+ bool isGlobal() const { return Def.Kind == MachineOperand::MO_GlobalAddress;
}
bool needsShrink() const { return ShrinkOpcode != -1; }
};
@@ -84,7 +183,7 @@ class SIFoldOperandsImpl {
const SIMachineFunctionInfo *MFI;
bool frameIndexMayFold(const MachineInstr &UseMI, int OpNo,
- const MachineOperand &OpToFold) const;
+ const FoldableDef &OpToFold) const;
// TODO: Just use TII::getVALUOp
unsigned convertToVALUOp(unsigned Opc, bool UseVOP3 = false) const {
@@ -112,11 +211,11 @@ class SIFoldOperandsImpl {
bool canUseImmWithOpSel(FoldCandidate &Fold) const;
- bool tryFoldImmWithOpSel(FoldCandidate &Fold) const;
+ bool tryFoldImmWithOpSel(FoldCandidate &Fold, int64_t ImmVal) const;
bool tryAddToFoldList(SmallVectorImpl<FoldCandidate> &FoldList,
MachineInstr *MI, unsigned OpNo,
- MachineOperand *OpToFold) const;
+ const FoldableDef &OpToFold) const;
bool isUseSafeToFold(const MachineInstr &MI,
const MachineOperand &UseMO) const;
@@ -135,12 +234,10 @@ class SIFoldOperandsImpl {
MachineOperand *SplatVal,
const TargetRegisterClass *SplatRC) const;
- bool tryToFoldACImm(MachineOperand &OpToFold, MachineInstr *UseMI,
+ bool tryToFoldACImm(const FoldableDef &OpToFold, MachineInstr *UseMI,
unsigned UseOpIdx,
SmallVectorImpl<FoldCandidate> &FoldList) const;
- void foldOperand(MachineOperand &OpToFold,
- MachineInstr *UseMI,
- int UseOpIdx,
+ void foldOperand(FoldableDef OpToFold, MachineInstr *UseMI, int UseOpIdx,
SmallVectorImpl<FoldCandidate> &FoldList,
SmallVectorImpl<MachineInstr *> &CopiesToReplace) const;
@@ -148,7 +245,7 @@ class SIFoldOperandsImpl {
bool tryConstantFoldOp(MachineInstr *MI) const;
bool tryFoldCndMask(MachineInstr &MI) const;
bool tryFoldZeroHighBits(MachineInstr &MI) const;
- bool foldInstOperand(MachineInstr &MI, MachineOperand &OpToFold) const;
+ bool foldInstOperand(MachineInstr &MI, const FoldableDef &OpToFold) const;
bool foldCopyToAGPRRegSequence(MachineInstr *CopyMI) const;
bool tryFoldFoldableCopy(MachineInstr &MI,
@@ -240,8 +337,8 @@ static unsigned macToMad(unsigned Opc) {
// TODO: Add heuristic that the frame index might not fit in the addressing
mode
// immediate offset to avoid materializing in loops.
-bool SIFoldOperandsImpl::frameIndexMayFold(
- const MachineInstr &UseMI, int OpNo, const MachineOperand &OpToFold) const
{
+bool SIFoldOperandsImpl::frameIndexMayFold(const MachineInstr &UseMI, int OpNo,
+ const FoldableDef &OpToFold) const {
if (!OpToFold.isFI())
return false;
@@ -381,7 +478,8 @@ bool SIFoldOperandsImpl::canUseImmWithOpSel(FoldCandidate
&Fold) const {
return true;
}
-bool SIFoldOperandsImpl::tryFoldImmWithOpSel(FoldCandidate &Fold) const {
+bool SIFoldOperandsImpl::tryFoldImmWithOpSel(FoldCandidate &Fold,
+ int64_t ImmVal) const {
MachineInstr *MI = Fold.UseMI;
MachineOperand &Old = MI->getOperand(Fold.UseOpNo);
unsigned Opcode = MI->getOpcode();
@@ -391,8 +489,8 @@ bool SIFoldOperandsImpl::tryFoldImmWithOpSel(FoldCandidate
&Fold) const {
// If the literal can be inlined as-is, apply it and short-circuit the
// tests below. The main motivation for this is to avoid unintuitive
// uses of opsel.
- if (AMDGPU::isInlinableLiteralV216(Fold.ImmToFold, OpType)) {
- Old.ChangeToImmediate(Fold.ImmToFold);
+ if (AMDGPU::isInlinableLiteralV216(ImmVal, OpType)) {
+ Old.ChangeToImmediate(ImmVal);
return true;
}
@@ -415,10 +513,10 @@ bool
SIFoldOperandsImpl::tryFoldImmWithOpSel(FoldCandidate &Fold) const {
MachineOperand &Mod = MI->getOperand(ModIdx);
unsigned ModVal = Mod.getImm();
- uint16_t ImmLo = static_cast<uint16_t>(
- Fold.ImmToFold >> (ModVal & SISrcMods::OP_SEL_0 ? 16 : 0));
- uint16_t ImmHi = static_cast<uint16_t>(
- Fold.ImmToFold >> (ModVal & SISrcMods::OP_SEL_1 ? 16 : 0));
+ uint16_t ImmLo =
+ static_cast<uint16_t>(ImmVal >> (ModVal & SISrcMods::OP_SEL_0 ? 16 : 0));
+ uint16_t ImmHi =
+ static_cast<uint16_t>(ImmVal >> (ModVal & SISrcMods::OP_SEL_1 ? 16 : 0));
uint32_t Imm = (static_cast<uint32_t>(ImmHi) << 16) | ImmLo;
unsigned NewModVal = ModVal & ~(SISrcMods::OP_SEL_0 | SISrcMods::OP_SEL_1);
@@ -510,16 +608,20 @@ bool SIFoldOperandsImpl::updateOperand(FoldCandidate
&Fold) const {
assert(Old.isReg());
if (Fold.isImm() && canUseImmWithOpSel(Fold)) {
- if (tryFoldImmWithOpSel(Fold))
+ std::optional<int64_t> ImmVal = Fold.Def.getEffectiveImmVal();
+ if (!ImmVal)
+ return false;
+
+ if (tryFoldImmWithOpSel(Fold, *ImmVal))
return true;
// We can't represent the candidate as an inline constant. Try as a literal
// with the original opsel, checking constant bus limitations.
- MachineOperand New = MachineOperand::CreateImm(Fold.ImmToFold);
+ MachineOperand New = MachineOperand::CreateImm(*ImmVal);
int OpNo = MI->getOperandNo(&Old);
if (!TII->isOperandLegal(*MI, OpNo, &New))
return false;
- Old.ChangeToImmediate(Fold.ImmToFold);
+ Old.ChangeToImmediate(*ImmVal);
return true;
}
@@ -575,22 +677,34 @@ bool SIFoldOperandsImpl::updateOperand(FoldCandidate
&Fold) const {
MI->setDesc(TII->get(NewMFMAOpc));
MI->untieRegOperand(0);
}
- Old.ChangeToImmediate(Fold.ImmToFold);
+
+ std::optional<int64_t> ImmVal = Fold.Def.getEffectiveImmVal();
+ if (!ImmVal)
+ return false;
+
+ // TODO: Should we try to avoid adding this to the candidate list?
+ MachineOperand New = MachineOperand::CreateImm(*ImmVal);
+ int OpNo = MI->getOperandNo(&Old);
+ if (!TII->isOperandLegal(*MI, OpNo, &New))
+ return false;
+
+ Old.ChangeToImmediate(*ImmVal);
return true;
}
if (Fold.isGlobal()) {
- Old.ChangeToGA(Fold.OpToFold->getGlobal(), Fold.OpToFold->getOffset(),
- Fold.OpToFold->getTargetFlags());
+ Old.ChangeToGA(Fold.Def.OpToFold->getGlobal(),
+ Fold.Def.OpToFold->getOffset(),
+ Fold.Def.OpToFold->getTargetFlags());
return true;
}
if (Fold.isFI()) {
- Old.ChangeToFrameIndex(Fold.FrameIndexToFold);
+ Old.ChangeToFrameIndex(Fold.getFI());
return true;
}
- MachineOperand *New = Fold.OpToFold;
+ MachineOperand *New = Fold.Def.OpToFold;
// Rework once the VS_16 register class is updated to include proper
// 16-bit SGPRs instead of 32-bit ones.
if (Old.getSubReg() == AMDGPU::lo16 && TRI->isSGPRReg(*MRI, New->getReg()))
@@ -613,26 +727,19 @@ static void
appendFoldCandidate(SmallVectorImpl<FoldCandidate> &FoldList,
static void appendFoldCandidate(SmallVectorImpl<FoldCandidate> &FoldList,
MachineInstr *MI, unsigned OpNo,
- MachineOperand *FoldOp, bool Commuted = false,
- int ShrinkOp = -1) {
- appendFoldCandidate(FoldList,
- FoldCandidate(MI, OpNo, FoldOp, Commuted, ShrinkOp));
-}
-
-static void appendFoldCandidate(SmallVectorImpl<FoldCandidate> &FoldList,
- MachineInstr *MI, unsigned OpNo, int64_t
ImmVal,
+ const FoldableDef &FoldOp,
bool Commuted = false, int ShrinkOp = -1) {
appendFoldCandidate(FoldList,
- FoldCandidate(MI, OpNo, ImmVal, Commuted, ShrinkOp));
+ FoldCandidate(MI, OpNo, FoldOp, Commuted, ShrinkOp));
}
bool SIFoldOperandsImpl::tryAddToFoldList(
SmallVectorImpl<FoldCandidate> &FoldList, MachineInstr *MI, unsigned OpNo,
- MachineOperand *OpToFold) const {
+ const FoldableDef &OpToFold) const {
const unsigned Opc = MI->getOpcode();
auto tryToFoldAsFMAAKorMK = [&]() {
- if (!OpToFold->isImm())
+ if (!OpToFold.isImm())
return false;
const bool TryAK = OpNo == 3;
@@ -665,8 +772,8 @@ bool SIFoldOperandsImpl::tryAddToFoldList(
return false;
};
- bool IsLegal = TII->isOperandLegal(*MI, OpNo, OpToFold);
- if (!IsLegal && OpToFold->isImm()) {
+ bool IsLegal = OpToFold.isOperandLegal(*TII, *MI, OpNo);
+ if (!IsLegal && OpToFold.isImm()) {
FoldCandidate Fold(MI, OpNo, OpToFold);
IsLegal = canUseImmWithOpSel(Fold);
}
@@ -700,7 +807,7 @@ bool SIFoldOperandsImpl::tryAddToFoldList(
}
// Special case for s_setreg_b32
- if (OpToFold->isImm()) {
+ if (OpToFold.isImm()) {
unsigned ImmOpc = 0;
if (Opc == AMDGPU::S_SETREG_B32)
ImmOpc = AMDGPU::S_SETREG_IMM32_B32;
@@ -741,10 +848,10 @@ bool SIFoldOperandsImpl::tryAddToFoldList(
return false;
int Op32 = -1;
- if (!TII->isOperandLegal(*MI, CommuteOpNo, OpToFold)) {
+ if (!OpToFold.isOperandLegal(*TII, *MI, CommuteOpNo)) {
if ((Opc != AMDGPU::V_ADD_CO_U32_e64 && Opc != AMDGPU::V_SUB_CO_U32_e64
&&
Opc != AMDGPU::V_SUBREV_CO_U32_e64) || // FIXME
- (!OpToFold->isImm() && !OpToFold->isFI() && !OpToFold->isGlobal())) {
+ (!OpToFold.isImm() && !OpToFold.isFI() && !OpToFold.isGlobal())) {
TII->commuteInstruction(*MI, false, OpNo, CommuteOpNo);
return false;
}
@@ -763,7 +870,8 @@ bool SIFoldOperandsImpl::tryAddToFoldList(
Op32 = AMDGPU::getVOPe32(MaybeCommutedOpc);
}
- appendFoldCandidate(FoldList, MI, CommuteOpNo, OpToFold, true, Op32);
+ appendFoldCandidate(FoldList, MI, CommuteOpNo, OpToFold, /*Commuted=*/true,
+ Op32);
return true;
}
@@ -938,7 +1046,7 @@ MachineOperand *SIFoldOperandsImpl::tryFoldRegSeqSplat(
}
bool SIFoldOperandsImpl::tryToFoldACImm(
- MachineOperand &OpToFold, MachineInstr *UseMI, unsigned UseOpIdx,
+ const FoldableDef &OpToFold, MachineInstr *UseMI, unsigned UseOpIdx,
SmallVectorImpl<FoldCandidate> &FoldList) const {
const MCInstrDesc &Desc = UseMI->getDesc();
if (UseOpIdx >= Desc.getNumOperands())
@@ -949,27 +1057,9 @@ bool SIFoldOperandsImpl::tryToFoldACImm(
return false;
MachineOperand &UseOp = UseMI->getOperand(UseOpIdx);
- if (OpToFold.isImm()) {
- if (unsigned UseSubReg = UseOp.getSubReg()) {
- std::optional<int64_t> SubImm =
- SIInstrInfo::extractSubregFromImm(OpToFold.getImm(), UseSubReg);
- if (!SubImm)
- return false;
-
- // TODO: Avoid the temporary MachineOperand
- MachineOperand TmpOp = MachineOperand::CreateImm(*SubImm);
- if (TII->isOperandLegal(*UseMI, UseOpIdx, &TmpOp)) {
- appendFoldCandidate(FoldList, UseMI, UseOpIdx, *SubImm);
- return true;
- }
-
- return false;
- }
-
- if (TII->isOperandLegal(*UseMI, UseOpIdx, &OpToFold)) {
- appendFoldCandidate(FoldList, UseMI, UseOpIdx, &OpToFold);
- return true;
- }
+ if (OpToFold.isImm() && OpToFold.isOperandLegal(*TII, *UseMI, UseOpIdx)) {
+ appendFoldCandidate(FoldList, UseMI, UseOpIdx, OpToFold);
+ return true;
}
// TODO: Verify the following code handles subregisters correctly.
@@ -985,11 +1075,17 @@ bool SIFoldOperandsImpl::tryToFoldACImm(
return false;
// Maybe it is just a COPY of an immediate itself.
+
+ // FIXME: Remove this handling. There is already special case folding of
+ // immediate into copy in foldOperand. This is looking for the def of the
+ // value the folding started from in the first place.
MachineInstr *Def = MRI->getVRegDef(UseReg);
if (Def && TII->isFoldableCopy(*Def)) {
MachineOperand &DefOp = Def->getOperand(1);
if (DefOp.isImm() && TII->isOperandLegal(*UseMI, UseOpIdx, &DefOp)) {
- appendFoldCandidate(FoldList, UseMI, UseOpIdx, &DefOp);
+ FoldableDef FoldableImm(DefOp.getImm(), OpToFold.DefRC,
+ OpToFold.DefSubReg);
+ appendFoldCandidate(FoldList, UseMI, UseOpIdx, FoldableImm);
return true;
}
}
@@ -998,7 +1094,7 @@ bool SIFoldOperandsImpl::tryToFoldACImm(
}
void SIFoldOperandsImpl::foldOperand(
- MachineOperand &OpToFold, MachineInstr *UseMI, int UseOpIdx,
+ FoldableDef OpToFold, MachineInstr *UseMI, int UseOpIdx,
SmallVectorImpl<FoldCandidate> &FoldList,
SmallVectorImpl<MachineInstr *> &CopiesToReplace) const {
const MachineOperand *UseOp = &UseMI->getOperand(UseOpIdx);
@@ -1038,18 +1134,20 @@ void SIFoldOperandsImpl::foldOperand(
if (SplatVal) {
if (MachineOperand *Foldable =
tryFoldRegSeqSplat(RSUseMI, OpNo, SplatVal, SplatRC)) {
- appendFoldCandidate(FoldList, RSUseMI, OpNo, Foldable);
+ FoldableDef SplatDef(*Foldable, SplatRC);
+ appendFoldCandidate(FoldList, RSUseMI, OpNo, SplatDef);
continue;
}
}
+ // TODO: Handle general compose
if (RSUse->getSubReg() != RegSeqDstSubReg)
continue;
- if (tryToFoldACImm(UseMI->getOperand(0), RSUseMI, OpNo, FoldList))
- continue;
-
- foldOperand(OpToFold, RSUseMI, OpNo, FoldList, CopiesToReplace);
+ // FIXME: We should avoid recursing here. There should be a cleaner split
+ // between the in-place mutations and adding to the fold list.
+ foldOperand(OpToFold, RSUseMI, RSUseMI->getOperandNo(RSUse), FoldList,
+ CopiesToReplace);
}
return;
@@ -1077,7 +1175,7 @@ void SIFoldOperandsImpl::foldOperand(
// A frame index will resolve to a positive constant, so it should always
be
// safe to fold the addressing mode, even pre-GFX9.
- UseMI->getOperand(UseOpIdx).ChangeToFrameIndex(OpToFold.getIndex());
+ UseMI->getOperand(UseOpIdx).ChangeToFrameIndex(OpToFold.getFI());
const unsigned Opc = UseMI->getOpcode();
if (TII->isFLATScratch(*UseMI) &&
@@ -1107,11 +1205,12 @@ void SIFoldOperandsImpl::foldOperand(
return;
const TargetRegisterClass *DestRC = TRI->getRegClassForReg(*MRI, DestReg);
- if (!DestReg.isPhysical()) {
- if (DestRC == &AMDGPU::AGPR_32RegClass &&
- TII->isInlineConstant(OpToFold, AMDGPU::OPERAND_REG_INLINE_C_INT32))
{
+ if (!DestReg.isPhysical() && DestRC == &AMDGPU::AGPR_32RegClass) {
+ std::optional<int64_t> UseImmVal = OpToFold.getEffectiveImmVal();
+ if (UseImmVal && TII->isInlineConstant(
+ *UseImmVal, AMDGPU::OPERAND_REG_INLINE_C_INT32)) {
UseMI->setDesc(TII->get(AMDGPU::V_ACCVGPR_WRITE_B32_e64));
- UseMI->getOperand(1).ChangeToImmediate(OpToFold.getImm());
+ UseMI->getOperand(1).ChangeToImmediate(*UseImmVal);
CopiesToReplace.push_back(UseMI);
return;
}
@@ -1167,8 +1266,9 @@ void SIFoldOperandsImpl::foldOperand(
if (UseMI->isCopy() && OpToFold.isReg() &&
UseMI->getOperand(0).getReg().isVirtual() &&
!UseMI->getOperand(1).getSubReg() &&
- OpToFold.getParent()->implicit_operands().empty()) {
- LLVM_DEBUG(dbgs() << "Folding " << OpToFold << "\n into " << *UseMI);
+ OpToFold.DefMI->implicit_operands().empty()) {
+ LLVM_DEBUG(dbgs() << "Folding " << OpToFold.OpToFold << "\n into "
+ << *UseMI);
unsigned Size = TII->getOpSize(*UseMI, 1);
Register UseReg = OpToFold.getReg();
UseMI->getOperand(1).setReg(UseReg);
@@ -1208,7 +1308,7 @@ void SIFoldOperandsImpl::foldOperand(
UseMI->getOperand(1).setSubReg(SubRegIdx);
UseMI->getOperand(1).setIsKill(false);
CopiesToReplace.push_back(UseMI);
- OpToFold.setIsKill(false);
+ OpToFold.OpToFold->setIsKill(false);
// Remove kill flags as kills may now be out of order with uses.
MRI->clearKillFlags(UseReg);
@@ -1228,21 +1328,21 @@ void SIFoldOperandsImpl::foldOperand(
if (FoldingImmLike) {
if (execMayBeModifiedBeforeUse(*MRI,
UseMI->getOperand(UseOpIdx).getReg(),
- *OpToFold.getParent(),
- *UseMI))
+ *OpToFold.DefMI, *UseMI))
return;
UseMI->setDesc(TII->get(AMDGPU::S_MOV_B32));
- if (OpToFold.isImm())
- UseMI->getOperand(1).ChangeToImmediate(OpToFold.getImm());
- else if (OpToFold.isFI())
- UseMI->getOperand(1).ChangeToFrameIndex(OpToFold.getIndex());
+ if (OpToFold.isImm()) {
+ UseMI->getOperand(1).ChangeToImmediate(
+ *OpToFold.getEffectiveImmVal());
+ } else if (OpToFold.isFI())
+ UseMI->getOperand(1).ChangeToFrameIndex(OpToFold.getFI());
else {
assert(OpToFold.isGlobal());
- UseMI->getOperand(1).ChangeToGA(OpToFold.getGlobal(),
- OpToFold.getOffset(),
- OpToFold.getTargetFlags());
+ UseMI->getOperand(1).ChangeToGA(OpToFold.OpToFold->getGlobal(),
+ OpToFold.OpToFold->getOffset(),
+ OpToFold.OpToFold->getTargetFlags());
}
UseMI->removeOperand(2); // Remove exec read (or src1 for readlane)
return;
@@ -1251,8 +1351,7 @@ void SIFoldOperandsImpl::foldOperand(
if (OpToFold.isReg() && TRI->isSGPRReg(*MRI, OpToFold.getReg())) {
if (execMayBeModifiedBeforeUse(*MRI,
UseMI->getOperand(UseOpIdx).getReg(),
- *OpToFold.getParent(),
- *UseMI))
+ *OpToFold.DefMI, *UseMI))
return;
// %vgpr = COPY %sgpr0
@@ -1294,7 +1393,7 @@ void SIFoldOperandsImpl::foldOperand(
return;
}
- tryAddToFoldList(FoldList, UseMI, UseOpIdx, &OpToFold);
+ tryAddToFoldList(FoldList, UseMI, UseOpIdx, OpToFold);
// FIXME: We could try to change the instruction from 64-bit to 32-bit
// to enable more folding opportunities. The shrink operands pass
@@ -1302,32 +1401,7 @@ void SIFoldOperandsImpl::foldOperand(
return;
}
-
- const MCInstrDesc &FoldDesc = OpToFold.getParent()->getDesc();
- const TargetRegisterClass *FoldRC =
- TRI->getRegClass(FoldDesc.operands()[0].RegClass);
-
- // Split 64-bit constants into 32-bits for folding.
- if (UseOp->getSubReg() && AMDGPU::getRegBitWidth(*FoldRC) == 64) {
- Register UseReg = UseOp->getReg();
- const TargetRegisterClass *UseRC = MRI->getRegClass(UseReg);
- if (AMDGPU::getRegBitWidth(*UseRC) != 64)
- return;
-
- APInt Imm(64, OpToFold.getImm());
- if (UseOp->getSubReg() == AMDGPU::sub0) {
- Imm = Imm.getLoBits(32);
- } else {
- assert(UseOp->getSubReg() == AMDGPU::sub1);
- Imm = Imm.getHiBits(32);
- }
-
- MachineOperand ImmOp = MachineOperand::CreateImm(Imm.getSExtValue());
- tryAddToFoldList(FoldList, UseMI, UseOpIdx, &ImmOp);
- return;
- }
-
- tryAddToFoldList(FoldList, UseMI, UseOpIdx, &OpToFold);
+ tryAddToFoldList(FoldList, UseMI, UseOpIdx, OpToFold);
}
static bool evalBinaryInstruction(unsigned Opcode, int32_t &Result,
@@ -1606,7 +1680,7 @@ bool SIFoldOperandsImpl::tryFoldZeroHighBits(MachineInstr
&MI) const {
}
bool SIFoldOperandsImpl::foldInstOperand(MachineInstr &MI,
- MachineOperand &OpToFold) const {
+ const FoldableDef &OpToFold) const {
// We need mutate the operands of new mov instructions to add implicit
// uses of EXEC, but adding them invalidates the use_iterator, so defer
// this.
@@ -1637,7 +1711,9 @@ bool SIFoldOperandsImpl::foldInstOperand(MachineInstr &MI,
llvm::make_pointer_range(MRI->use_nodbg_operands(Dst.getReg())));
for (auto *U : UsesToProcess) {
MachineInstr *UseMI = U->getParent();
- foldOperand(OpToFold, UseMI, UseMI->getOperandNo(U), FoldList,
+
+ FoldableDef SubOpToFold = OpToFold.getWithSubReg(*TRI, U->getSubReg());
+ foldOperand(SubOpToFold, UseMI, UseMI->getOperandNo(U), FoldList,
CopiesToReplace);
}
@@ -1650,10 +1726,10 @@ bool SIFoldOperandsImpl::foldInstOperand(MachineInstr
&MI,
Copy->addImplicitDefUseOperands(*MF);
for (FoldCandidate &Fold : FoldList) {
- assert(!Fold.isReg() || Fold.OpToFold);
- if (Fold.isReg() && Fold.OpToFold->getReg().isVirtual()) {
- Register Reg = Fold.OpToFold->getReg();
- MachineInstr *DefMI = Fold.OpToFold->getParent();
+ assert(!Fold.isReg() || Fold.Def.OpToFold);
+ if (Fold.isReg() && Fold.getReg().isVirtual()) {
+ Register Reg = Fold.getReg();
+ const MachineInstr *DefMI = Fold.Def.DefMI;
if (DefMI->readsRegister(AMDGPU::EXEC, TRI) &&
execMayBeModifiedBeforeUse(*MRI, Reg, *DefMI, *Fold.UseMI))
continue;
@@ -1661,11 +1737,11 @@ bool SIFoldOperandsImpl::foldInstOperand(MachineInstr
&MI,
if (updateOperand(Fold)) {
// Clear kill flags.
if (Fold.isReg()) {
- assert(Fold.OpToFold && Fold.OpToFold->isReg());
+ assert(Fold.Def.OpToFold && Fold.isReg());
// FIXME: Probably shouldn't bother trying to fold if not an
// SGPR. PeepholeOptimizer can eliminate redundant VGPR->VGPR
// copies.
- MRI->clearKillFlags(Fold.OpToFold->getReg());
+ MRI->clearKillFlags(Fold.getReg());
}
LLVM_DEBUG(dbgs() << "Folded source from " << MI << " into OpNo "
<< static_cast<int>(Fold.UseOpNo) << " of "
@@ -1847,6 +1923,18 @@ bool SIFoldOperandsImpl::tryFoldFoldableCopy(
if (OpToFold.isReg() && !OpToFold.getReg().isVirtual())
return false;
+ // Prevent folding operands backwards in the function. For example,
+ // the COPY opcode must not be replaced by 1 in this example:
+ //
+ // %3 = COPY %vgpr0; VGPR_32:%3
+ // ...
+ // %vgpr0 = V_MOV_B32_e32 1, implicit %exec
+ if (!DstReg.isVirtual())
+ return false;
+
+ const TargetRegisterClass *DstRC =
+ MRI->getRegClass(MI.getOperand(0).getReg());
+
// True16: Fix malformed 16-bit sgpr COPY produced by peephole-opt
// Can remove this code if proper 16-bit SGPRs are implemented
// Example: Pre-peephole-opt
@@ -1863,8 +1951,6 @@ bool SIFoldOperandsImpl::tryFoldFoldableCopy(
// %30:sreg_32 = S_PACK_LL_B32_B16 killed %31:sreg_32, killed %16:sreg_32
if (MI.getOpcode() == AMDGPU::COPY && OpToFold.isReg() &&
OpToFold.getSubReg()) {
- const TargetRegisterClass *DstRC =
- MRI->getRegClass(MI.getOperand(0).getReg());
if (DstRC == &AMDGPU::SReg_32RegClass &&
DstRC == MRI->getRegClass(OpToFold.getReg())) {
assert(OpToFold.getSubReg() == AMDGPU::lo16);
@@ -1872,15 +1958,6 @@ bool SIFoldOperandsImpl::tryFoldFoldableCopy(
}
}
- // Prevent folding operands backwards in the function. For example,
- // the COPY opcode must not be replaced by 1 in this example:
- //
- // %3 = COPY %vgpr0; VGPR_32:%3
- // ...
- // %vgpr0 = V_MOV_B32_e32 1, implicit %exec
- if (!DstReg.isVirtual())
- return false;
-
if (OpToFold.isReg() &&
foldCopyToVGPROfScalarAddOfFrameIndex(DstReg, OpToFold.getReg(), MI))
return true;
@@ -1892,7 +1969,8 @@ bool SIFoldOperandsImpl::tryFoldFoldableCopy(
return true;
}
- bool Changed = foldInstOperand(MI, OpToFold);
+ FoldableDef Def(OpToFold, DstRC);
+ bool Changed = foldInstOperand(MI, Def);
// If we managed to fold all uses of this copy then we might as well
// delete it now.
diff --git
a/llvm/test/CodeGen/AMDGPU/issue139317-bad-opsel-reg-sequence-fold.ll
b/llvm/test/CodeGen/AMDGPU/issue139317-bad-opsel-reg-sequence-fold.ll
index 7d1ea68e63241..f18a657b8082d 100644
--- a/llvm/test/CodeGen/AMDGPU/issue139317-bad-opsel-reg-sequence-fold.ll
+++ b/llvm/test/CodeGen/AMDGPU/issue139317-bad-opsel-reg-sequence-fold.ll
@@ -16,6 +16,7 @@ define amdgpu_kernel void
@stepper_test_kernel_DType_I6A6AcB6A6AsA6A6A_68a5362b9
; GFX942-NEXT: s_load_dwordx4 s[0:3], s[4:5], 0x0
; GFX942-NEXT: s_mov_b32 s8, 0x47004600
; GFX942-NEXT: s_mov_b32 s9, 0x45004400
+; GFX942-NEXT: s_mov_b32 s10, 0x42004000
; GFX942-NEXT: s_mov_b64 s[4:5], 0
; GFX942-NEXT: v_mov_b32_e32 v2, 0
; GFX942-NEXT: v_mov_b64_e32 v[0:1], s[6:7]
@@ -29,7 +30,7 @@ define amdgpu_kernel void
@stepper_test_kernel_DType_I6A6AcB6A6AsA6A6A_68a5362b9
; GFX942-NEXT: s_waitcnt vmcnt(0)
; GFX942-NEXT: v_pk_add_f16 v7, v7, s8
; GFX942-NEXT: v_pk_add_f16 v6, v6, s9
-; GFX942-NEXT: v_pk_add_f16 v5, v5, 0
+; GFX942-NEXT: v_pk_add_f16 v5, v5, s10
; GFX942-NEXT: v_pk_add_f16 v4, v4, 1.0 op_sel:[0,1] op_sel_hi:[1,0]
; GFX942-NEXT: global_store_dwordx4 v2, v[4:7], s[0:1]
; GFX942-NEXT: s_add_u32 s0, s0, 16
diff --git a/llvm/test/CodeGen/AMDGPU/si-fold-operands-subreg-imm.gfx942.mir
b/llvm/test/CodeGen/AMDGPU/si-fold-operands-subreg-imm.gfx942.mir
index c1ce216955dca..98b179fb5f2a8 100644
--- a/llvm/test/CodeGen/AMDGPU/si-fold-operands-subreg-imm.gfx942.mir
+++ b/llvm/test/CodeGen/AMDGPU/si-fold-operands-subreg-imm.gfx942.mir
@@ -18,7 +18,7 @@ body: |
; CHECK-NEXT: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 1107312640
; CHECK-NEXT: [[S_MOV_B32_1:%[0-9]+]]:sreg_32 = S_MOV_B32 1006632960
; CHECK-NEXT: [[REG_SEQUENCE:%[0-9]+]]:sgpr_64 = REG_SEQUENCE killed
[[S_MOV_B32_1]], %subreg.sub0, killed [[S_MOV_B32_]], %subreg.sub1
- ; CHECK-NEXT: [[V_PK_ADD_F16_:%[0-9]+]]:vgpr_32 = nofpexcept V_PK_ADD_F16
8, [[COPY]], 8, 0, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
+ ; CHECK-NEXT: [[V_PK_ADD_F16_:%[0-9]+]]:vgpr_32 = nofpexcept V_PK_ADD_F16
8, [[COPY]], 8, [[REG_SEQUENCE]].sub1, 0, 0, 0, 0, 0, implicit $mode, implicit
$exec
; CHECK-NEXT: S_ENDPGM 0, implicit [[V_PK_ADD_F16_]]
%0:vgpr_32 = COPY $vgpr0
%1:sreg_32 = S_MOV_B32 1107312640
@@ -99,7 +99,7 @@ body: |
; CHECK-NEXT: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 -16
; CHECK-NEXT: [[S_MOV_B32_1:%[0-9]+]]:sreg_32 = S_MOV_B32 1006632960
; CHECK-NEXT: [[REG_SEQUENCE:%[0-9]+]]:sgpr_64 = REG_SEQUENCE killed
[[S_MOV_B32_1]], %subreg.sub0, killed [[S_MOV_B32_]], %subreg.sub1
- ; CHECK-NEXT: [[V_PK_ADD_F16_:%[0-9]+]]:vgpr_32 = nofpexcept V_PK_ADD_F16
8, [[COPY]], 8, 4294967295, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
+ ; CHECK-NEXT: [[V_PK_ADD_F16_:%[0-9]+]]:vgpr_32 = nofpexcept V_PK_ADD_F16
8, [[COPY]], 8, -16, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
; CHECK-NEXT: S_ENDPGM 0, implicit [[V_PK_ADD_F16_]]
%0:vgpr_32 = COPY $vgpr0
%1:sreg_32 = S_MOV_B32 -16
@@ -123,7 +123,7 @@ body: |
; CHECK-NEXT: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 15360
; CHECK-NEXT: [[S_MOV_B32_1:%[0-9]+]]:sreg_32 = S_MOV_B32 1006632960
; CHECK-NEXT: [[REG_SEQUENCE:%[0-9]+]]:sgpr_64 = REG_SEQUENCE killed
[[S_MOV_B32_1]], %subreg.sub0, killed [[S_MOV_B32_]], %subreg.sub1
- ; CHECK-NEXT: [[V_PK_ADD_F16_:%[0-9]+]]:vgpr_32 = nofpexcept V_PK_ADD_F16
8, [[COPY]], 8, 0, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
+ ; CHECK-NEXT: [[V_PK_ADD_F16_:%[0-9]+]]:vgpr_32 = nofpexcept V_PK_ADD_F16
8, [[COPY]], 8, 15360, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
; CHECK-NEXT: S_ENDPGM 0, implicit [[V_PK_ADD_F16_]]
%0:vgpr_32 = COPY $vgpr0
%1:sreg_32 = S_MOV_B32 15360
@@ -147,7 +147,7 @@ body: |
; CHECK-NEXT: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 1006632960
; CHECK-NEXT: [[S_MOV_B32_1:%[0-9]+]]:sreg_32 = S_MOV_B32 15360
; CHECK-NEXT: [[REG_SEQUENCE:%[0-9]+]]:sgpr_64 = REG_SEQUENCE killed
[[S_MOV_B32_1]], %subreg.sub0, killed [[S_MOV_B32_]], %subreg.sub1
- ; CHECK-NEXT: [[V_PK_ADD_F16_:%[0-9]+]]:vgpr_32 = nofpexcept V_PK_ADD_F16
8, [[COPY]], 8, 0, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
+ ; CHECK-NEXT: [[V_PK_ADD_F16_:%[0-9]+]]:vgpr_32 = nofpexcept V_PK_ADD_F16
8, [[COPY]], 4, 15360, 0, 0, 0, 0, 0, implicit $mode, implicit $exec
; CHECK-NEXT: S_ENDPGM 0, implicit [[V_PK_ADD_F16_]]
%0:vgpr_32 = COPY $vgpr0
%1:sreg_32 = S_MOV_B32 1006632960
diff --git a/llvm/test/CodeGen/AMDGPU/si-fold-operands-subreg-imm.mir
b/llvm/test/CodeGen/AMDGPU/si-fold-operands-subreg-imm.mir
index 38b4533a14895..1742349673d7c 100644
--- a/llvm/test/CodeGen/AMDGPU/si-fold-operands-subreg-imm.mir
+++ b/llvm/test/CodeGen/AMDGPU/si-fold-operands-subreg-imm.mir
@@ -115,8 +115,8 @@ body: |
; CHECK-NEXT: [[COPY:%[0-9]+]]:sgpr_64 = COPY $sgpr8_sgpr9
; CHECK-NEXT: [[S_MOV_B64_:%[0-9]+]]:sreg_64 = S_MOV_B64 8
; CHECK-NEXT: [[REG_SEQUENCE:%[0-9]+]]:sreg_64 = REG_SEQUENCE
[[S_MOV_B64_]].sub1, %subreg.sub0, [[S_MOV_B64_]].sub0, %subreg.sub1
- ; CHECK-NEXT: [[S_ADD_U32_:%[0-9]+]]:sreg_32 = S_ADD_U32 [[COPY]].sub0, 8,
implicit-def $scc
- ; CHECK-NEXT: [[S_ADDC_U32_:%[0-9]+]]:sreg_32 = S_ADDC_U32 [[COPY]].sub1,
0, implicit-def $scc, implicit $scc
+ ; CHECK-NEXT: [[S_ADD_U32_:%[0-9]+]]:sreg_32 = S_ADD_U32 [[COPY]].sub0, 0,
implicit-def $scc
+ ; CHECK-NEXT: [[S_ADDC_U32_:%[0-9]+]]:sreg_32 = S_ADDC_U32 [[COPY]].sub1,
8, implicit-def $scc, implicit $scc
; CHECK-NEXT: S_ENDPGM 0, implicit [[S_ADD_U32_]], implicit [[S_ADDC_U32_]]
%0:sgpr_64 = COPY $sgpr8_sgpr9
%1:sreg_64 = S_MOV_B64 8
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