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[SelectionDAG] Stop storing EVTs in a function scoped static std::set. #118715

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merged 2 commits into from
Dec 5, 2024
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[SelectionDAG] Stop storing EVTs in a function scoped static std::set. #118715

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267aa0f
[SelectionDAG] Stop storing EVTs in a function scoped static std::set.
topperc Apr 24, 2024
c001489
fixup! Move std::set into SelectionDAG instead of reusing FoldingSet.
topperc Dec 5, 2024
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4 changes: 4 additions & 0 deletions llvm/include/llvm/CodeGen/SelectionDAG.h
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@
#include <cstdint>
#include <functional>
#include <map>
#include <set>
#include <string>
#include <tuple>
#include <utility>
Expand Down Expand Up @@ -247,6 +248,9 @@ class SelectionDAG {
BlockFrequencyInfo *BFI = nullptr;
MachineModuleInfo *MMI = nullptr;

/// Extended EVTs used for single value VTLists.
std::set<EVT, EVT::compareRawBits> EVTs;
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@arsenm arsenm Dec 5, 2024

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Did you try all the set types? Does DenseSet do any better?

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@topperc topperc Dec 5, 2024

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I didn't try DenseSEt. Looks like we would need to add a DenseMapInfo for EVT including defining Empty and Tombstone values?

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@arsenm arsenm Dec 5, 2024

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Yes

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@efriedma-quic efriedma-quic Dec 5, 2024

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The usage here depends on the address stability of the map entries (the VTList points at the map's key), and DenseSet doesn't provide that. So you'd need define a struct like EVTSetKey Key { EVT* Ptr; };, define DenseMapInfo for that, then use DenseSet<EVTSetKey>.

I guess you could do that, but it seems like overkill.


/// List of non-single value types.
FoldingSet<SDVTListNode> VTListMap;

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4 changes: 2 additions & 2 deletions llvm/include/llvm/CodeGen/SelectionDAGNodes.h
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Expand Up @@ -664,7 +664,7 @@ END_TWO_BYTE_PACK()
DebugLoc debugLoc;

/// Return a pointer to the specified value type.
static const EVT *getValueTypeList(EVT VT);
static const EVT *getValueTypeList(MVT VT);

/// Index in worklist of DAGCombiner, or negative if the node is not in the
/// worklist. -1 = not in worklist; -2 = not in worklist, but has already been
Expand Down Expand Up @@ -1124,7 +1124,7 @@ END_TWO_BYTE_PACK()
void addUse(SDUse &U) { U.addToList(&UseList); }

protected:
static SDVTList getSDVTList(EVT VT) {
static SDVTList getSDVTList(MVT VT) {
SDVTList Ret = { getValueTypeList(VT), 1 };
return Ret;
}
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17 changes: 7 additions & 10 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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Expand Up @@ -10623,7 +10623,10 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
}

SDVTList SelectionDAG::getVTList(EVT VT) {
return makeVTList(SDNode::getValueTypeList(VT), 1);
if (!VT.isExtended())
return makeVTList(SDNode::getValueTypeList(VT.getSimpleVT()), 1);

return makeVTList(&(*EVTs.insert(VT).first), 1);
}

SDVTList SelectionDAG::getVTList(EVT VT1, EVT VT2) {
Expand Down Expand Up @@ -12383,17 +12386,11 @@ namespace {

/// getValueTypeList - Return a pointer to the specified value type.
///
const EVT *SDNode::getValueTypeList(EVT VT) {
static std::set<EVT, EVT::compareRawBits> EVTs;
const EVT *SDNode::getValueTypeList(MVT VT) {
static EVTArray SimpleVTArray;
static sys::SmartMutex<true> VTMutex;

if (VT.isExtended()) {
sys::SmartScopedLock<true> Lock(VTMutex);
return &(*EVTs.insert(VT).first);
}
assert(VT.getSimpleVT() < MVT::VALUETYPE_SIZE && "Value type out of range!");
return &SimpleVTArray.VTs[VT.getSimpleVT().SimpleTy];
assert(VT < MVT::VALUETYPE_SIZE && "Value type out of range!");
return &SimpleVTArray.VTs[VT.SimpleTy];
}

/// hasNUsesOfValue - Return true if there are exactly NUSES uses of the
Expand Down
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