/// \brief Simplify arithmetic intrinsics with overflow and known identity
/// constants such as 0 and 1.
/// If this returns a value other than SILValue() then the instruction was
/// simplified to a value which doesn't overflow. The overflow case is handled
/// in SILCombine.
static SILValue simplifyBinaryWithOverflow(BuiltinInst *BI,
llvm::Intrinsic::ID ID) {
OperandValueArrayRef Args = BI->getArguments();
assert(Args.size() >= 2);
const SILValue &Op1 = Args[0];
const SILValue &Op2 = Args[1];
auto *IntOp1 = dyn_cast<IntegerLiteralInst>(Op1);
auto *IntOp2 = dyn_cast<IntegerLiteralInst>(Op2);
// If both ops are not constants, we cannot do anything.
// FIXME: Add cases where we can do something, eg, (x - x) -> 0
if (!IntOp1 && !IntOp2)
return SILValue();
// Calculate the result.
switch (ID) {
default: llvm_unreachable("Invalid case");
case llvm::Intrinsic::sadd_with_overflow:
case llvm::Intrinsic::uadd_with_overflow:
// 0 + X -> X
if (match(Op1, m_Zero()))
return Op2;
// X + 0 -> X
if (match(Op2, m_Zero()))
return Op1;
return SILValue();
case llvm::Intrinsic::ssub_with_overflow:
case llvm::Intrinsic::usub_with_overflow:
// X - 0 -> X
if (match(Op2, m_Zero()))
return Op1;
return SILValue();
case llvm::Intrinsic::smul_with_overflow:
case llvm::Intrinsic::umul_with_overflow:
// 0 * X -> 0
if (match(Op1, m_Zero()))
return Op1;
// X * 0 -> 0
if (match(Op2, m_Zero()))
return Op2;
// 1 * X -> X
if (match(Op1, m_One()))
return Op2;
// X * 1 -> X
if (match(Op2, m_One()))
return Op1;
return SILValue();
}
return SILValue();
}
/// Like ValueIsPHI but also check if the PHI has no source
/// operands, i.e., it was just added.
static SILPhiArgument *ValueIsNewPHI(SILValue Val, SILSSAUpdater *Updater) {
SILPhiArgument *PHI = ValueIsPHI(Val, Updater);
if (PHI) {
auto *PhiBB = PHI->getParent();
size_t PhiIdx = PHI->getIndex();
// If all predecessor edges are 'not set' this is a new phi.
for (auto *PredBB : PhiBB->getPredecessorBlocks()) {
OperandValueArrayRef Edges =
getEdgeValuesForTerminator(PredBB->getTerminator(), PhiBB);
assert(PhiIdx < Edges.size() && "Not enough edges!");
SILValue V = Edges[PhiIdx];
// Check for the 'not set' sentinel.
if (V != Updater->PHISentinel.get())
return nullptr;
}
return PHI;
}
return nullptr;
}
/// We rotated a loop if it has the following properties.
///
/// * It has an exiting header with a conditional branch.
/// * It has a preheader (the function will try to create one for critical edges
/// from cond_br).
///
/// We will rotate at most up to the basic block passed as an argument.
/// We will not rotate a loop where the header is equal to the latch except is
/// RotateSingleBlockLoops is true.
///
/// Note: The code relies on the 'UpTo' basic block to stay within the rotate
/// loop for termination.
bool swift::rotateLoop(SILLoop *L, DominanceInfo *DT, SILLoopInfo *LI,
bool RotateSingleBlockLoops, SILBasicBlock *UpTo,
bool ShouldVerify) {
assert(L != nullptr && DT != nullptr && LI != nullptr &&
"Missing loop information");
auto *Header = L->getHeader();
if (!Header)
return false;
// We need a preheader - this is also a canonicalization for follow-up
// passes.
auto *Preheader = L->getLoopPreheader();
if (!Preheader) {
LLVM_DEBUG(llvm::dbgs() << *L << " no preheader\n");
LLVM_DEBUG(L->getHeader()->getParent()->dump());
return false;
}
if (!RotateSingleBlockLoops && (Header == UpTo || isSingleBlockLoop(L)))
return false;
assert(RotateSingleBlockLoops || L->getBlocks().size() != 1);
// Need a conditional branch that guards the entry into the loop.
auto *LoopEntryBranch = dyn_cast<CondBranchInst>(Header->getTerminator());
if (!LoopEntryBranch)
return false;
// The header needs to exit the loop.
if (!L->isLoopExiting(Header)) {
LLVM_DEBUG(llvm::dbgs() << *L << " not an exiting header\n");
LLVM_DEBUG(L->getHeader()->getParent()->dump());
return false;
}
// We need a single backedge and the latch must not exit the loop if it is
// also the header.
auto *Latch = L->getLoopLatch();
if (!Latch) {
LLVM_DEBUG(llvm::dbgs() << *L << " no single latch\n");
return false;
}
// Make sure we can duplicate the header.
SmallVector<SILInstruction *, 8> MoveToPreheader;
if (!canDuplicateOrMoveToPreheader(L, Preheader, Header, MoveToPreheader)) {
LLVM_DEBUG(llvm::dbgs() << *L
<< " instructions in header preventing rotating\n");
return false;
}
auto *NewHeader = LoopEntryBranch->getTrueBB();
auto *Exit = LoopEntryBranch->getFalseBB();
if (L->contains(Exit))
std::swap(NewHeader, Exit);
assert(L->contains(NewHeader) && !L->contains(Exit) &&
"Could not find loop header and exit block");
// We don't want to rotate such that we merge two headers of separate loops
// into one. This can be turned into an assert again once we have guaranteed
// preheader insertions.
if (!NewHeader->getSinglePredecessorBlock() && Header != Latch)
return false;
// Now that we know we can perform the rotation - move the instructions that
// need moving.
for (auto *Inst : MoveToPreheader)
Inst->moveBefore(Preheader->getTerminator());
LLVM_DEBUG(llvm::dbgs() << " Rotating " << *L);
// Map the values for the duplicated header block. We are duplicating the
// header instructions into the end of the preheader.
llvm::DenseMap<ValueBase *, SILValue> ValueMap;
// The original 'phi' argument values are just the values coming from the
// preheader edge.
ArrayRef<SILArgument *> PHIs = Header->getArguments();
OperandValueArrayRef PreheaderArgs =
cast<BranchInst>(Preheader->getTerminator())->getArgs();
assert(PHIs.size() == PreheaderArgs.size() &&
"Basic block arguments and incoming edge mismatch");
// Here we also store the value index to use into the value map (versus
// non-argument values where the operand use decides which value index to
// use).
for (unsigned Idx = 0, E = PHIs.size(); Idx != E; ++Idx)
ValueMap[PHIs[Idx]] = PreheaderArgs[Idx];
// The other instructions are just cloned to the preheader.
TermInst *PreheaderBranch = Preheader->getTerminator();
for (auto &Inst : *Header) {
if (SILInstruction *cloned = Inst.clone(PreheaderBranch)) {
mapOperands(cloned, ValueMap);
// The actual operand will sort out which result idx to use.
auto instResults = Inst.getResults();
auto clonedResults = cloned->getResults();
assert(instResults.size() == clonedResults.size());
for (auto i : indices(instResults))
ValueMap[instResults[i]] = clonedResults[i];
}
}
PreheaderBranch->dropAllReferences();
PreheaderBranch->eraseFromParent();
// If there were any uses of instructions in the duplicated loop entry check
// block rewrite them using the ssa updater.
rewriteNewLoopEntryCheckBlock(Header, Preheader, ValueMap);
L->moveToHeader(NewHeader);
// Now the original preheader dominates all of headers children and the
// original latch dominates the header.
updateDomTree(DT, Preheader, Latch, Header);
assert(DT->getNode(NewHeader)->getIDom() == DT->getNode(Preheader));
assert(!DT->dominates(Header, Exit) ||
DT->getNode(Exit)->getIDom() == DT->getNode(Preheader));
assert(DT->getNode(Header)->getIDom() == DT->getNode(Latch) ||
((Header == Latch) &&
DT->getNode(Header)->getIDom() == DT->getNode(Preheader)));
// Beautify the IR. Move the old header to after the old latch as it is now
// the latch.
Header->moveAfter(Latch);
// Merge the old latch with the old header if possible.
mergeBasicBlockWithSuccessor(Latch, DT, LI);
// Create a new preheader.
splitIfCriticalEdge(Preheader, NewHeader, DT, LI);
if (ShouldVerify) {
DT->verify();
LI->verify();
Latch->getParent()->verify();
}
LLVM_DEBUG(llvm::dbgs() << " to " << *L);
LLVM_DEBUG(L->getHeader()->getParent()->dump());
return true;
}
/// \brief Changes the edge value between a branch and destination basic block
/// at the specified index. Changes all edges from \p Branch to \p Dest to carry
/// the value.
///
/// \param Branch The branch to modify.
/// \param Dest The destination of the edge.
/// \param Idx The index of the argument to modify.
/// \param Val The new value to use.
/// \return The new branch. Deletes the old one.
/// Changes the edge value between a branch and destination basic block at the
/// specified index.
TermInst *swift::changeEdgeValue(TermInst *Branch, SILBasicBlock *Dest,
size_t Idx, SILValue Val) {
SILBuilderWithScope Builder(Branch);
if (CondBranchInst *CBI = dyn_cast<CondBranchInst>(Branch)) {
SmallVector<SILValue, 8> TrueArgs;
SmallVector<SILValue, 8> FalseArgs;
OperandValueArrayRef OldTrueArgs = CBI->getTrueArgs();
bool BranchOnTrue = CBI->getTrueBB() == Dest;
assert((!BranchOnTrue || Idx < OldTrueArgs.size()) && "Not enough edges");
// Copy the edge values overwriting the edge at Idx.
for (unsigned i = 0, e = OldTrueArgs.size(); i != e; ++i) {
if (BranchOnTrue && Idx == i)
TrueArgs.push_back(Val);
else
TrueArgs.push_back(OldTrueArgs[i]);
}
assert(TrueArgs.size() == CBI->getTrueBB()->getNumBBArg() &&
"Destination block's number of arguments must match");
OperandValueArrayRef OldFalseArgs = CBI->getFalseArgs();
bool BranchOnFalse = CBI->getFalseBB() == Dest;
assert((!BranchOnFalse || Idx < OldFalseArgs.size()) && "Not enough edges");
// Copy the edge values overwriting the edge at Idx.
for (unsigned i = 0, e = OldFalseArgs.size(); i != e; ++i) {
if (BranchOnFalse && Idx == i)
FalseArgs.push_back(Val);
else
FalseArgs.push_back(OldFalseArgs[i]);
}
assert(FalseArgs.size() == CBI->getFalseBB()->getNumBBArg() &&
"Destination block's number of arguments must match");
CBI = Builder.createCondBranch(CBI->getLoc(), CBI->getCondition(),
CBI->getTrueBB(), TrueArgs,
CBI->getFalseBB(), FalseArgs);
Branch->dropAllReferences();
Branch->eraseFromParent();
return CBI;
}
if (BranchInst *BI = dyn_cast<BranchInst>(Branch)) {
SmallVector<SILValue, 8> Args;
assert(Idx < BI->getNumArgs() && "Not enough edges");
OperandValueArrayRef OldArgs = BI->getArgs();
// Copy the edge values overwriting the edge at Idx.
for (unsigned i = 0, e = OldArgs.size(); i != e; ++i) {
if (Idx == i)
Args.push_back(Val);
else
Args.push_back(OldArgs[i]);
}
assert(Args.size() == Dest->getNumBBArg());
BI = Builder.createBranch(BI->getLoc(), BI->getDestBB(), Args);
Branch->dropAllReferences();
Branch->eraseFromParent();
return BI;
}
llvm_unreachable("Unhandled terminator leading to merge block");
}
SILValue getValueForBlock(size_t Idx, SILBasicBlock *BB, TermInst *TI) {
OperandValueArrayRef Args = getEdgeValuesForTerminator(TI, BB);
assert(Idx < Args.size() && "Not enough values on incoming edge");
return Args[Idx];
}
SILInstruction *
SILCombiner::optimizeApplyOfConvertFunctionInst(FullApplySite AI,
ConvertFunctionInst *CFI) {
// We only handle simplification of static function references. If we don't
// have one, bail.
FunctionRefInst *FRI = dyn_cast<FunctionRefInst>(CFI->getOperand());
if (!FRI)
return nullptr;
// Grab our relevant callee types...
CanSILFunctionType SubstCalleeTy = AI.getSubstCalleeType();
auto ConvertCalleeTy =
CFI->getOperand()->getType().castTo<SILFunctionType>();
// ... and make sure they have no unsubstituted generics. If they do, bail.
if (SubstCalleeTy->hasArchetype() || ConvertCalleeTy->hasArchetype())
return nullptr;
// Ok, we can now perform our transformation. Grab AI's operands and the
// relevant types from the ConvertFunction function type and AI.
Builder.setCurrentDebugScope(AI.getDebugScope());
OperandValueArrayRef Ops = AI.getArgumentsWithoutIndirectResults();
auto OldOpTypes = SubstCalleeTy->getParameterSILTypes();
auto NewOpTypes = ConvertCalleeTy->getParameterSILTypes();
assert(Ops.size() == OldOpTypes.size() &&
"Ops and op types must have same size.");
assert(Ops.size() == NewOpTypes.size() &&
"Ops and op types must have same size.");
llvm::SmallVector<SILValue, 8> Args;
for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
SILValue Op = Ops[i];
SILType OldOpType = OldOpTypes[i];
SILType NewOpType = NewOpTypes[i];
// Convert function takes refs to refs, address to addresses, and leaves
// other types alone.
if (OldOpType.isAddress()) {
assert(NewOpType.isAddress() && "Addresses should map to addresses.");
auto UAC = Builder.createUncheckedAddrCast(AI.getLoc(), Op, NewOpType);
Args.push_back(UAC);
} else if (OldOpType.isHeapObjectReferenceType()) {
assert(NewOpType.isHeapObjectReferenceType() &&
"refs should map to refs.");
auto URC = Builder.createUncheckedRefCast(AI.getLoc(), Op, NewOpType);
Args.push_back(URC);
} else {
Args.push_back(Op);
}
}
SILType CCSILTy = SILType::getPrimitiveObjectType(ConvertCalleeTy);
// Create the new apply inst.
SILInstruction *NAI;
if (auto *TAI = dyn_cast<TryApplyInst>(AI))
NAI = Builder.createTryApply(AI.getLoc(), FRI, CCSILTy,
ArrayRef<Substitution>(), Args,
TAI->getNormalBB(), TAI->getErrorBB());
else
NAI = Builder.createApply(AI.getLoc(), FRI, CCSILTy,
ConvertCalleeTy->getSILResult(),
ArrayRef<Substitution>(), Args,
cast<ApplyInst>(AI)->isNonThrowing());
return NAI;
}
/// \brief Fold arithmetic intrinsics with overflow.
static SILInstruction *
constantFoldBinaryWithOverflow(BuiltinInst *BI, llvm::Intrinsic::ID ID,
bool ReportOverflow,
Optional<bool> &ResultsInError) {
OperandValueArrayRef Args = BI->getArguments();
assert(Args.size() >= 2);
auto *Op1 = dyn_cast<IntegerLiteralInst>(Args[0]);
auto *Op2 = dyn_cast<IntegerLiteralInst>(Args[1]);
// If either Op1 or Op2 is not a literal, we cannot do anything.
if (!Op1 || !Op2)
return nullptr;
// Calculate the result.
APInt LHSInt = Op1->getValue();
APInt RHSInt = Op2->getValue();
bool Overflow;
APInt Res = constantFoldBinaryWithOverflow(LHSInt, RHSInt, Overflow, ID);
// If we can statically determine that the operation overflows,
// warn about it if warnings are not disabled by ResultsInError being null.
if (ResultsInError.hasValue() && Overflow && ReportOverflow) {
// Try to infer the type of the constant expression that the user operates
// on. If the intrinsic was lowered from a call to a function that takes
// two arguments of the same type, use the type of the LHS argument.
// This would detect '+'/'+=' and such.
Type OpType;
SILLocation Loc = BI->getLoc();
const ApplyExpr *CE = Loc.getAsASTNode<ApplyExpr>();
SourceRange LHSRange, RHSRange;
if (CE) {
const auto *Args = dyn_cast_or_null<TupleExpr>(CE->getArg());
if (Args && Args->getNumElements() == 2) {
// Look through inout types in order to handle += well.
CanType LHSTy = Args->getElement(0)->getType()->getInOutObjectType()->
getCanonicalType();
CanType RHSTy = Args->getElement(1)->getType()->getCanonicalType();
if (LHSTy == RHSTy)
OpType = Args->getElement(1)->getType();
LHSRange = Args->getElement(0)->getSourceRange();
RHSRange = Args->getElement(1)->getSourceRange();
}
}
bool Signed = false;
StringRef Operator = "+";
switch (ID) {
default: llvm_unreachable("Invalid case");
case llvm::Intrinsic::sadd_with_overflow:
Signed = true;
break;
case llvm::Intrinsic::uadd_with_overflow:
break;
case llvm::Intrinsic::ssub_with_overflow:
Operator = "-";
Signed = true;
break;
case llvm::Intrinsic::usub_with_overflow:
Operator = "-";
break;
case llvm::Intrinsic::smul_with_overflow:
Operator = "*";
Signed = true;
break;
case llvm::Intrinsic::umul_with_overflow:
Operator = "*";
break;
}
if (!OpType.isNull()) {
diagnose(BI->getModule().getASTContext(),
Loc.getSourceLoc(),
diag::arithmetic_operation_overflow,
LHSInt.toString(/*Radix*/ 10, Signed),
Operator,
RHSInt.toString(/*Radix*/ 10, Signed),
OpType).highlight(LHSRange).highlight(RHSRange);
} else {
// If we cannot get the type info in an expected way, describe the type.
diagnose(BI->getModule().getASTContext(),
Loc.getSourceLoc(),
diag::arithmetic_operation_overflow_generic_type,
LHSInt.toString(/*Radix*/ 10, Signed),
Operator,
RHSInt.toString(/*Radix*/ 10, Signed),
Signed,
LHSInt.getBitWidth()).highlight(LHSRange).highlight(RHSRange);
}
ResultsInError = Optional<bool>(true);
}
return constructResultWithOverflowTuple(BI, Res, Overflow);
}
