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[X86] Avoid repeated hash lookups (NFC) #130710

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Merged
merged 2 commits into from
Mar 11, 2025
Merged

[X86] Avoid repeated hash lookups (NFC) #130710

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[X86] Avoid repeated hash lookups (NFC)
kazutakahirata Mar 10, 2025
82aa6f0
Address a comment.
kazutakahirata Mar 11, 2025
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28 changes: 15 additions & 13 deletions llvm/lib/Target/X86/X86PreTileConfig.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -293,29 +293,30 @@ bool X86PreTileConfig::runOnMachineFunction(MachineFunction &MF) {
SmallVector<MachineBasicBlock *, 8> CfgLiveInBBs;
for (auto &MBB : MF) {
size_t Pos = 0;
auto &Info = BBVisitedInfo[&MBB];
for (auto &MI : MBB) {
++Pos;
if (isAMXInstruction(MI)) {
// If there's call before the AMX, we need to reload tile config.
if (BBVisitedInfo[&MBB].LastCall)
CfgNeedInsert.insert(BBVisitedInfo[&MBB].LastCall);
if (Info.LastCall)
CfgNeedInsert.insert(Info.LastCall);
else // Otherwise, we need tile config to live in this BB.
BBVisitedInfo[&MBB].NeedTileCfgLiveIn = true;
Info.NeedTileCfgLiveIn = true;
// Always record the first AMX in case there's shape def after it.
if (!BBVisitedInfo[&MBB].FirstAMX)
BBVisitedInfo[&MBB].FirstAMX = MIRef(&MI, &MBB, Pos);
if (!Info.FirstAMX)
Info.FirstAMX = MIRef(&MI, &MBB, Pos);
} else if (MI.isCall() && isDestructiveCall(MI, AMXRegs)) {
// Record the call only if the callee clobbers all AMX registers.
BBVisitedInfo[&MBB].LastCall = MIRef(&MI, &MBB, Pos);
Info.LastCall = MIRef(&MI, &MBB, Pos);
}
}
if (BBVisitedInfo[&MBB].NeedTileCfgLiveIn) {
if (Info.NeedTileCfgLiveIn) {
if (&MBB == &MF.front())
CfgNeedInsert.insert(MIRef(&MBB));
else
CfgLiveInBBs.push_back(&MBB);
}
if (BBVisitedInfo[&MBB].FirstAMX || BBVisitedInfo[&MBB].HasAMXRegLiveIn)
if (Info.FirstAMX || Info.HasAMXRegLiveIn)
for (auto *Succ : MBB.successors())
if (!isLoopBackEdge(Succ, &MBB))
BBVisitedInfo[Succ].HasAMXRegLiveIn = true;
Expand Down Expand Up @@ -344,16 +345,16 @@ bool X86PreTileConfig::runOnMachineFunction(MachineFunction &MF) {
// Avoid to insert ldtilecfg before any shape defs.
SmallVector<MachineBasicBlock *, 8> WorkList;
for (auto &I : ShapeBBs) {
auto &Info = BBVisitedInfo[I.first];
// TODO: We can hoist shapes across BBs here.
if (BBVisitedInfo[I.first].HasAMXRegLiveIn) {
if (Info.HasAMXRegLiveIn) {
// We are not able to config tile registers since the shape to config
// is not defined yet. Emit error message and continue. The function
// would not config tile registers.
emitErrorMsg(MF);
return false;
}
if (BBVisitedInfo[I.first].FirstAMX &&
BBVisitedInfo[I.first].FirstAMX < I.second.back() &&
if (Info.FirstAMX && Info.FirstAMX < I.second.back() &&
!hoistShapesInBB(I.first, I.second)) {
emitErrorMsg(MF);
return false;
Expand All @@ -363,8 +364,9 @@ bool X86PreTileConfig::runOnMachineFunction(MachineFunction &MF) {
while (!WorkList.empty()) {
MachineBasicBlock *MBB = WorkList.pop_back_val();
for (auto *Pred : MBB->predecessors()) {
if (!BBVisitedInfo[Pred].TileCfgForbidden && !isLoopBackEdge(MBB, Pred)) {
BBVisitedInfo[Pred].TileCfgForbidden = true;
auto &Info = BBVisitedInfo[Pred];
if (!Info.TileCfgForbidden && !isLoopBackEdge(MBB, Pred)) {
Info.TileCfgForbidden = true;
WorkList.push_back(Pred);
}
}
Expand Down