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path: root/llvm/lib/CodeGen/ModuloSchedule.cpp
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Diffstat (limited to 'llvm/lib/CodeGen/ModuloSchedule.cpp')
-rw-r--r--llvm/lib/CodeGen/ModuloSchedule.cpp75
1 files changed, 54 insertions, 21 deletions
diff --git a/llvm/lib/CodeGen/ModuloSchedule.cpp b/llvm/lib/CodeGen/ModuloSchedule.cpp
index 581168b..d689e8e 100644
--- a/llvm/lib/CodeGen/ModuloSchedule.cpp
+++ b/llvm/lib/CodeGen/ModuloSchedule.cpp
@@ -116,6 +116,12 @@ void ModuloScheduleExpander::generatePipelinedLoop() {
// a map between register names in the original block and the names created
// in each stage of the pipelined loop.
ValueMapTy *VRMap = new ValueMapTy[(MaxStageCount + 1) * 2];
+
+ // The renaming destination by Phis for the registers across stages.
+ // This map is updated during Phis generation to point to the most recent
+ // renaming destination.
+ ValueMapTy *VRMapPhi = new ValueMapTy[(MaxStageCount + 1) * 2];
+
InstrMapTy InstrMap;
SmallVector<MachineBasicBlock *, 4> PrologBBs;
@@ -151,14 +157,15 @@ void ModuloScheduleExpander::generatePipelinedLoop() {
generateExistingPhis(KernelBB, PrologBBs.back(), KernelBB, KernelBB, VRMap,
InstrMap, MaxStageCount, MaxStageCount, false);
- generatePhis(KernelBB, PrologBBs.back(), KernelBB, KernelBB, VRMap, InstrMap,
- MaxStageCount, MaxStageCount, false);
+ generatePhis(KernelBB, PrologBBs.back(), KernelBB, KernelBB, VRMap, VRMapPhi,
+ InstrMap, MaxStageCount, MaxStageCount, false);
LLVM_DEBUG(dbgs() << "New block\n"; KernelBB->dump(););
SmallVector<MachineBasicBlock *, 4> EpilogBBs;
// Generate the epilog instructions to complete the pipeline.
- generateEpilog(MaxStageCount, KernelBB, BB, VRMap, EpilogBBs, PrologBBs);
+ generateEpilog(MaxStageCount, KernelBB, BB, VRMap, VRMapPhi, EpilogBBs,
+ PrologBBs);
// We need this step because the register allocation doesn't handle some
// situations well, so we insert copies to help out.
@@ -171,6 +178,7 @@ void ModuloScheduleExpander::generatePipelinedLoop() {
addBranches(*Preheader, PrologBBs, KernelBB, EpilogBBs, VRMap);
delete[] VRMap;
+ delete[] VRMapPhi;
}
void ModuloScheduleExpander::cleanup() {
@@ -242,7 +250,8 @@ void ModuloScheduleExpander::generateProlog(unsigned LastStage,
/// block for each stage that needs to complete.
void ModuloScheduleExpander::generateEpilog(
unsigned LastStage, MachineBasicBlock *KernelBB, MachineBasicBlock *OrigBB,
- ValueMapTy *VRMap, MBBVectorTy &EpilogBBs, MBBVectorTy &PrologBBs) {
+ ValueMapTy *VRMap, ValueMapTy *VRMapPhi, MBBVectorTy &EpilogBBs,
+ MBBVectorTy &PrologBBs) {
// We need to change the branch from the kernel to the first epilog block, so
// this call to analyze branch uses the kernel rather than the original BB.
MachineBasicBlock *TBB = nullptr, *FBB = nullptr;
@@ -296,8 +305,8 @@ void ModuloScheduleExpander::generateEpilog(
}
generateExistingPhis(NewBB, PrologBBs[i - 1], PredBB, KernelBB, VRMap,
InstrMap, LastStage, EpilogStage, i == 1);
- generatePhis(NewBB, PrologBBs[i - 1], PredBB, KernelBB, VRMap, InstrMap,
- LastStage, EpilogStage, i == 1);
+ generatePhis(NewBB, PrologBBs[i - 1], PredBB, KernelBB, VRMap, VRMapPhi,
+ InstrMap, LastStage, EpilogStage, i == 1);
PredBB = NewBB;
LLVM_DEBUG({
@@ -593,8 +602,9 @@ void ModuloScheduleExpander::generateExistingPhis(
/// use in the pipelined sequence.
void ModuloScheduleExpander::generatePhis(
MachineBasicBlock *NewBB, MachineBasicBlock *BB1, MachineBasicBlock *BB2,
- MachineBasicBlock *KernelBB, ValueMapTy *VRMap, InstrMapTy &InstrMap,
- unsigned LastStageNum, unsigned CurStageNum, bool IsLast) {
+ MachineBasicBlock *KernelBB, ValueMapTy *VRMap, ValueMapTy *VRMapPhi,
+ InstrMapTy &InstrMap, unsigned LastStageNum, unsigned CurStageNum,
+ bool IsLast) {
// Compute the stage number that contains the initial Phi value, and
// the Phi from the previous stage.
unsigned PrologStage = 0;
@@ -631,26 +641,49 @@ void ModuloScheduleExpander::generatePhis(
if (!InKernel && (unsigned)StageScheduled > PrologStage)
continue;
- unsigned PhiOp2 = VRMap[PrevStage][Def];
- if (MachineInstr *InstOp2 = MRI.getVRegDef(PhiOp2))
- if (InstOp2->isPHI() && InstOp2->getParent() == NewBB)
- PhiOp2 = getLoopPhiReg(*InstOp2, BB2);
+ unsigned PhiOp2;
+ if (InKernel) {
+ PhiOp2 = VRMap[PrevStage][Def];
+ if (MachineInstr *InstOp2 = MRI.getVRegDef(PhiOp2))
+ if (InstOp2->isPHI() && InstOp2->getParent() == NewBB)
+ PhiOp2 = getLoopPhiReg(*InstOp2, BB2);
+ }
// The number of Phis can't exceed the number of prolog stages. The
// prolog stage number is zero based.
if (NumPhis > PrologStage + 1 - StageScheduled)
NumPhis = PrologStage + 1 - StageScheduled;
for (unsigned np = 0; np < NumPhis; ++np) {
+ // Example for
+ // Org:
+ // %Org = ... (Scheduled at Stage#0, NumPhi = 2)
+ //
+ // Prolog0 (Stage0):
+ // %Clone0 = ...
+ // Prolog1 (Stage1):
+ // %Clone1 = ...
+ // Kernel (Stage2):
+ // %Phi0 = Phi %Clone1, Prolog1, %Clone2, Kernel
+ // %Phi1 = Phi %Clone0, Prolog1, %Phi0, Kernel
+ // %Clone2 = ...
+ // Epilog0 (Stage3):
+ // %Phi2 = Phi %Clone1, Prolog1, %Clone2, Kernel
+ // %Phi3 = Phi %Clone0, Prolog1, %Phi0, Kernel
+ // Epilog1 (Stage4):
+ // %Phi4 = Phi %Clone0, Prolog0, %Phi2, Epilog0
+ //
+ // VRMap = {0: %Clone0, 1: %Clone1, 2: %Clone2}
+ // VRMapPhi (after Kernel) = {0: %Phi1, 1: %Phi0}
+ // VRMapPhi (after Epilog0) = {0: %Phi3, 1: %Phi2}
+
unsigned PhiOp1 = VRMap[PrologStage][Def];
if (np <= PrologStage)
PhiOp1 = VRMap[PrologStage - np][Def];
- if (MachineInstr *InstOp1 = MRI.getVRegDef(PhiOp1)) {
- if (InstOp1->isPHI() && InstOp1->getParent() == KernelBB)
- PhiOp1 = getInitPhiReg(*InstOp1, KernelBB);
- if (InstOp1->isPHI() && InstOp1->getParent() == NewBB)
- PhiOp1 = getInitPhiReg(*InstOp1, NewBB);
+ if (!InKernel) {
+ if (PrevStage == LastStageNum && np == 0)
+ PhiOp2 = VRMap[LastStageNum][Def];
+ else
+ PhiOp2 = VRMapPhi[PrevStage - np][Def];
}
- if (!InKernel)
- PhiOp2 = VRMap[PrevStage - np][Def];
const TargetRegisterClass *RC = MRI.getRegClass(Def);
Register NewReg = MRI.createVirtualRegister(RC);
@@ -672,9 +705,9 @@ void ModuloScheduleExpander::generatePhis(
NewReg);
PhiOp2 = NewReg;
- VRMap[PrevStage - np - 1][Def] = NewReg;
+ VRMapPhi[PrevStage - np - 1][Def] = NewReg;
} else {
- VRMap[CurStageNum - np][Def] = NewReg;
+ VRMapPhi[CurStageNum - np][Def] = NewReg;
if (np == NumPhis - 1)
rewriteScheduledInstr(NewBB, InstrMap, CurStageNum, np, &*BBI, Def,
NewReg);
generated by cgit v1.1 at 2025-09-30 02:22:52 +0000