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[SILCombine] Dominance check for inject_enum_addr. #73040

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Merged
merged 2 commits into from
Apr 16, 2024
Merged

[SILCombine] Dominance check for inject_enum_addr. #73040

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7fbf22c
[NFC] SIL: Add hook to print after every subpass.
nate-chandler Apr 9, 2024
3070f83
[SILCombine] Dominance check for inject_enum_addr.
nate-chandler Apr 15, 2024
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18 changes: 16 additions & 2 deletions lib/SILOptimizer/PassManager/PassManager.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -204,6 +204,11 @@ static llvm::cl::opt<DebugOnlyPassNumberOpt, true,
llvm::cl::location(DebugOnlyPassNumberOptLoc),
llvm::cl::ValueRequired);

static llvm::cl::opt<bool> SILPrintEverySubpass(
"sil-print-every-subpass", llvm::cl::init(false),
llvm::cl::desc("Print the function before every subpass run of passes that "
"have multiple subpasses"));

static bool isInPrintFunctionList(SILFunction *F) {
for (const std::string &printFnName : SILPrintFunction) {
if (printFnName == F->getName())
Expand Down Expand Up @@ -478,13 +483,22 @@ bool SILPassManager::continueTransforming() {
bool SILPassManager::continueWithNextSubpassRun(SILInstruction *forInst,
SILFunction *function,
SILTransform *trans) {
unsigned subPass = numSubpassesRun++;

if (forInst && isFunctionSelectedForPrinting(function) &&
SILPrintEverySubpass) {
dumpPassInfo("*** SIL function before ", trans, function);
if (forInst) {
llvm::dbgs() << " *** sub-pass " << subPass << " for " << *forInst;
}
function->dump(getOptions().EmitVerboseSIL);
}

if (isMandatory)
return true;
if (NumPassesRun != maxNumPassesToRun - 1)
return true;

unsigned subPass = numSubpassesRun++;

if (subPass == maxNumSubpassesToRun - 1 && SILPrintLast) {
dumpPassInfo("*** SIL function before ", trans, function);
if (forInst) {
Expand Down
86 changes: 61 additions & 25 deletions lib/SILOptimizer/SILCombiner/SILCombinerMiscVisitors.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -865,14 +865,20 @@ SILInstruction *SILCombiner::visitCondFailInst(CondFailInst *CFI) {
return nullptr;
}

/// Create a value from stores to an address.
/// Whether there exists a unique value to which \p addr is always initialized
/// at \p forInst.
///
/// If there are only stores to \p addr, return the stored value. Also, if there
/// are address projections, create aggregate instructions for it.
/// If builder is null, it's just a dry-run to check if it's possible.
static SILValue createValueFromAddr(SILValue addr, SILBuilder *builder,
SILLocation loc) {
SmallVector<SILValue, 4> elems;
/// If \p builder is passed, create the value using it. If \p addr is
/// initialized piecewise via initializations of tuple element memory, the full
/// tuple is constructed via the builder.
///
/// A best effort.
/// TODO: Construct structs.
/// Handle stores of identical values on multiple paths.
static std::optional<std::pair<SILValue, SILInstruction *>>
createValueFromAddr(SILValue addr, SILInstruction *forInst, DominanceInfo *DI,
SILBuilder *builder, SILLocation loc) {
SmallVector<std::optional<std::pair<SILValue, SILInstruction *>>, 4> pairs;
enum Kind {
none, store, tuple
} kind = none;
Expand All @@ -884,7 +890,7 @@ static SILValue createValueFromAddr(SILValue addr, SILBuilder *builder,

auto *st = dyn_cast<StoreInst>(user);
if (st && kind == none && st->getDest() == addr) {
elems.push_back(st->getSrc());
pairs.push_back({{st->getSrc(), st}});
kind = store;
// We cannot just return st->getSrc() here because we also have to check
// if the store destination is the only use of addr.
Expand All @@ -893,35 +899,55 @@ static SILValue createValueFromAddr(SILValue addr, SILBuilder *builder,

if (auto *telem = dyn_cast<TupleElementAddrInst>(user)) {
if (kind == none) {
elems.resize(addr->getType().castTo<TupleType>()->getNumElements());
pairs.resize(addr->getType().castTo<TupleType>()->getNumElements());
kind = tuple;
}
if (kind == tuple) {
if (elems[telem->getFieldIndex()])
return SILValue();
elems[telem->getFieldIndex()] = createValueFromAddr(telem, builder, loc);
if (pairs[telem->getFieldIndex()]) {
// Already found a tuple_element_addr at this index. Assume that a
// different value is stored to addr by it.
return std::nullopt;
}
pairs[telem->getFieldIndex()] =
createValueFromAddr(telem, forInst, DI, builder, loc);
continue;
}
}
// TODO: handle StructElementAddrInst to create structs.

return SILValue();
return std::nullopt;
}
switch (kind) {
case none:
return SILValue();
return std::nullopt;
case store:
assert(elems.size() == 1);
return elems[0];
assert(pairs.size() == 1);
{
auto pair = pairs[0];
assert(pair.has_value());
bool isEmpty = pair->first->getType().isEmpty(*addr->getFunction());
if (isEmpty && !DI->properlyDominates(pair->second, forInst))
return std::nullopt;
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@meg-gupta meg-gupta Apr 15, 2024 •
edited
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Looks like without the dominance check here, we can have bad SIL with non empty types too!?

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Good point, we can't have them here either because that would imply there was a memory location whose type is non-empty which wasn't initialized on some path, which is invalid SIL.

return pair;
}
case tuple:
if (std::any_of(elems.begin(), elems.end(),
[](SILValue v){ return !(bool)v; }))
return SILValue();
if (std::any_of(pairs.begin(), pairs.end(), [&](auto pair) {
return !pair.has_value() ||
(pair->first->getType().isEmpty(*addr->getFunction()) &&
!DI->properlyDominates(pair->second, forInst));
}))
return std::nullopt;
if (builder) {
return builder->createTuple(loc, addr->getType().getObjectType(), elems);
SmallVector<SILValue, 4> elements;
for (auto pair : pairs) {
elements.push_back(pair->first);
}
auto *tuple =
builder->createTuple(loc, addr->getType().getObjectType(), elements);
return {{tuple, tuple}};
}
// Just return anything not null for the dry-run.
return elems[0];
return pairs[0];
}
llvm_unreachable("invalid kind");
}
Expand Down Expand Up @@ -1185,9 +1211,12 @@ SILCombiner::visitInjectEnumAddrInst(InjectEnumAddrInst *IEAI) {
// store %payload1 to %elem1_addr
// inject_enum_addr %enum_addr, $EnumType.case
//
if (createValueFromAddr(DataAddrInst, nullptr, DataAddrInst->getLoc())) {
SILValue en =
createValueFromAddr(DataAddrInst, &Builder, DataAddrInst->getLoc());
auto DI = DA->get(IEAI->getFunction());
if (createValueFromAddr(DataAddrInst, IEAI, DI, nullptr,
DataAddrInst->getLoc())) {
SILValue en = createValueFromAddr(DataAddrInst, IEAI, DI, &Builder,
DataAddrInst->getLoc())
->first;
assert(en);

// In that case, create the payload enum/store.
Expand Down Expand Up @@ -1224,7 +1253,14 @@ SILCombiner::visitInjectEnumAddrInst(InjectEnumAddrInst *IEAI) {
// store %1 to %nopayload_addr
//
auto *AI = dyn_cast_or_null<ApplyInst>(getSingleNonDebugUser(DataAddrInst));
if (!AI)
bool hasEmptyAssociatedType =
IEAI->getElement()->hasAssociatedValues()
? IEAI->getOperand()
->getType()
.getEnumElementType(IEAI->getElement(), func)
.isEmpty(*func)
: false;
if (!AI || (hasEmptyAssociatedType && !DI->properlyDominates(AI, IEAI)))
return nullptr;

unsigned ArgIdx = 0;
Expand Down
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