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[llvm][CodeGen] Add a new software pipeliner 'Window Scheduler' #84443

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Merged
merged 5 commits into from
Jun 13, 2024
Merged

[llvm][CodeGen] Add a new software pipeliner 'Window Scheduler' #84443

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3b47b44
[llvm][CodeGen] Add a new software pipeliner 'Window Scheduler'
huaatian Mar 8, 2024
1b5498c
[llvm][CodeGen] Revise some review comments #1
huaatian Mar 12, 2024
d461195
[llvm][CodeGen] Modifications made based on review comments 2
huaatian Apr 7, 2024
9355471
[llvm][CodeGen] Modifications made based on review comments 3
huaatian May 10, 2024
1bdbfa4
[llvm][CodeGen] Modifications made based on review comments 4
huaatian May 11, 2024
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12 changes: 6 additions & 6 deletions llvm/lib/CodeGen/WindowScheduler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -195,7 +195,7 @@ bool WindowScheduler::initialize() {
SmallVector<Register, 8> PhiDefs;
auto PLI = TII->analyzeLoopForPipelining(MBB);
for (auto &MI : *MBB) {
if (MI.isDebugInstr() || MI.isTerminator())
if (MI.isMetaInstruction() || MI.isTerminator())
continue;
if (MI.isPHI()) {
for (auto Def : PhiDefs)
Expand All @@ -222,7 +222,7 @@ bool WindowScheduler::initialize() {
"window scheduling!\n");
return false;
}
for (auto &Def : MI.defs())
for (auto &Def : MI.all_defs())
if (Def.isReg() && Def.getReg().isPhysical())
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Can this ignore dead defs?

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Yes, we believe that dead defs do not need a special handling process.

return false;
}
Expand Down Expand Up @@ -285,7 +285,7 @@ void WindowScheduler::generateTripleMBB() {
// DefPairs hold the old and new define register pairs.
DenseMap<Register, Register> DefPairs;
for (auto *MI : OriMIs) {
if (MI->isDebugInstr() || MI->isTerminator())
if (MI->isMetaInstruction() || MI->isTerminator())
continue;
if (MI->isPHI())
if (Register AntiReg = getAntiRegister(MI))
Expand All @@ -300,13 +300,13 @@ void WindowScheduler::generateTripleMBB() {
// are updated accordingly.
for (size_t Cnt = 1; Cnt < DuplicateNum; ++Cnt) {
for (auto *MI : OriMIs) {
if (MI->isPHI() || MI->isDebugInstr() ||
if (MI->isPHI() || MI->isMetaInstruction() ||
(MI->isTerminator() && Cnt < DuplicateNum - 1))
continue;
auto *NewMI = MF->CloneMachineInstr(MI);
DenseMap<Register, Register> NewDefs;
// New defines are updated.
for (auto MO : NewMI->defs())
for (auto MO : NewMI->all_defs())
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All these type of changes should have tests to go with them

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Okay, we have added test cases for dead def, implicit-def, and meta instruction.

if (MO.isReg() && MO.getReg().isVirtual()) {
Register NewDef =
MRI->createVirtualRegister(MRI->getRegClass(MO.getReg()));
Expand Down Expand Up @@ -666,7 +666,7 @@ unsigned WindowScheduler::getOriStage(MachineInstr *OriMI, unsigned Offset) {
// while the rest are set to 1.
unsigned Id = 0;
for (auto *MI : OriMIs) {
if (MI->isDebugInstr())
if (MI->isMetaInstruction())
continue;
if (MI == OriMI)
break;
Expand Down