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Reapply [AMDGPU] Avoid resource propagation for recursion through multiple functions #112251

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Merged
merged 8 commits into from
Nov 15, 2024
Merged

Reapply [AMDGPU] Avoid resource propagation for recursion through multiple functions #112251

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1b88285
Reapply [AMDGPU] Avoid resource propagation for recursion through mul…
JanekvO Oct 14, 2024
5463971
Feedback, merge WorkList iteration in Callee iteration
JanekvO Oct 15, 2024
ba27cd9
Recursive walk instead of iterative over a WorkSet
JanekvO Oct 23, 2024
f99b859
Feedback: remove redundant check
JanekvO Oct 31, 2024
b18ed55
Move isSymbolUsedInExpression to MCExpr, use for recursion detection …
JanekvO Nov 8, 2024
a72d1ef
Merge remote-tracking branch 'fork-github/main' into reapply-fix-recu…
JanekvO Nov 11, 2024
a60c29f
Conservative register count for recursion, comments, add reg usage in…
JanekvO Nov 13, 2024
8a38d54
Add register use for introduced tests
JanekvO Nov 15, 2024
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81 changes: 41 additions & 40 deletions llvm/lib/Target/AMDGPU/AMDGPUMCResourceInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -96,34 +96,48 @@ MCSymbol *MCResourceInfo::getMaxSGPRSymbol(MCContext &OutContext) {
// true if Sym is found within Expr (i.e., has a recurrance of Sym found), false
// otherwise.
static bool findSymbolInExpr(MCSymbol *Sym, const MCExpr *Expr,
SmallPtrSetImpl<const MCExpr *> &Exprs) {
SmallPtrSetImpl<const MCExpr *> &Visited) {

if (Expr->getKind() == MCExpr::ExprKind::SymbolRef) {
const MCSymbolRefExpr *SymRefExpr = cast<MCSymbolRefExpr>(Expr);
const MCSymbol &SymRef = SymRefExpr->getSymbol();
if (Sym == &SymRef)
return true;
}

if (!Visited.insert(Expr).second)
return false;

switch (Expr->getKind()) {
default:
return false;
case MCExpr::ExprKind::SymbolRef: {
const MCSymbolRefExpr *SymRefExpr = cast<MCSymbolRefExpr>(Expr);
const MCSymbol &SymRef = SymRefExpr->getSymbol();
if (Sym == &SymRef)
return true;
if (SymRef.isVariable())
Exprs.insert(SymRef.getVariableValue(/*isUsed=*/false));
if (SymRef.isVariable()) {
return findSymbolInExpr(Sym, SymRef.getVariableValue(/*isUsed=*/false),
Visited);
}
return false;
}
case MCExpr::ExprKind::Binary: {
const MCBinaryExpr *BExpr = cast<MCBinaryExpr>(Expr);
Exprs.insert(BExpr->getLHS());
Exprs.insert(BExpr->getRHS());
if (findSymbolInExpr(Sym, BExpr->getLHS(), Visited) ||
findSymbolInExpr(Sym, BExpr->getRHS(), Visited)) {
return true;
}
return false;
}
case MCExpr::ExprKind::Unary: {
const MCUnaryExpr *UExpr = cast<MCUnaryExpr>(Expr);
Exprs.insert(UExpr->getSubExpr());
return false;
return findSymbolInExpr(Sym, UExpr->getSubExpr(), Visited);
}
case MCExpr::ExprKind::Target: {
const AMDGPUMCExpr *AGVK = cast<AMDGPUMCExpr>(Expr);
for (const MCExpr *E : AGVK->getArgs())
Exprs.insert(E);
for (const MCExpr *E : AGVK->getArgs()) {
if (findSymbolInExpr(Sym, E, Visited))
return true;
}
return false;
}
}
Expand All @@ -146,24 +160,17 @@ void MCResourceInfo::assignResourceInfoExpr(
if (!Seen.insert(Callee).second)
continue;

SmallPtrSet<const MCExpr *, 8> WorkSet;
SmallPtrSet<const MCExpr *, 8> Visited;
MCSymbol *CalleeValSym = getSymbol(Callee->getName(), RIK, OutContext);
if (CalleeValSym->isVariable())
WorkSet.insert(CalleeValSym->getVariableValue(/*IsUsed=*/false));
else
ArgExprs.push_back(MCSymbolRefExpr::create(CalleeValSym, OutContext));

bool FoundRecursion = false;
while (!WorkSet.empty() && !FoundRecursion) {
auto It = WorkSet.begin();
const MCExpr *Expr = *It;
WorkSet.erase(Expr);

FoundRecursion = findSymbolInExpr(Sym, Expr, WorkSet);
}
bool CalleeIsVar = CalleeValSym->isVariable();

if (CalleeValSym->isVariable() && !FoundRecursion)
if (!CalleeIsVar ||
(CalleeIsVar &&
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@arsenm arsenm Oct 30, 2024

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CalleeIsVar && redundant

!findSymbolInExpr(Sym,
CalleeValSym->getVariableValue(/*IsUsed=*/false),
Visited))) {
ArgExprs.push_back(MCSymbolRefExpr::create(CalleeValSym, OutContext));
}
}
if (ArgExprs.size() > 1)
SymVal = AMDGPUMCExpr::create(Kind, ArgExprs, OutContext);
Expand Down Expand Up @@ -219,24 +226,18 @@ void MCResourceInfo::gatherResourceInfo(
if (!Seen.insert(Callee).second)
continue;
if (!Callee->isDeclaration()) {
SmallPtrSet<const MCExpr *, 8> WorkSet;
SmallPtrSet<const MCExpr *, 8> Visited;
MCSymbol *CalleeValSym =
getSymbol(Callee->getName(), RIK_PrivateSegSize, OutContext);
if (CalleeValSym->isVariable())
WorkSet.insert(CalleeValSym->getVariableValue(/*IsUsed=*/false));
else
ArgExprs.push_back(MCSymbolRefExpr::create(CalleeValSym, OutContext));
bool CalleeIsVar = CalleeValSym->isVariable();

bool FoundRecursion = false;
while (!WorkSet.empty() && !FoundRecursion) {
auto It = WorkSet.begin();
const MCExpr *Expr = *It;
WorkSet.erase(Expr);

FoundRecursion = findSymbolInExpr(Sym, Expr, WorkSet);
}
if (CalleeValSym->isVariable() && !FoundRecursion)
if (!CalleeIsVar ||
(CalleeIsVar &&
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@arsenm arsenm Oct 30, 2024

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CalleeIsVar && is redundant here

!findSymbolInExpr(Sym,
CalleeValSym->getVariableValue(/*IsUsed=*/false),
Visited))) {
ArgExprs.push_back(MCSymbolRefExpr::create(CalleeValSym, OutContext));
}
}
}
const MCExpr *localConstExpr =
Expand Down
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