/// Determine the number of iterations the loop is at most executed. The loop
/// might contain early exits so this is the maximum if no early exits are
/// taken.
static Optional<uint64_t> getMaxLoopTripCount(SILLoop *Loop,
SILBasicBlock *Preheader,
SILBasicBlock *Header,
SILBasicBlock *Latch) {
// Skip a split backedge.
SILBasicBlock *OrigLatch = Latch;
if (!Loop->isLoopExiting(Latch) && !(Latch = Latch->getSinglePredecessor()))
return None;
if (!Loop->isLoopExiting(Latch))
return None;
// Get the loop exit condition.
auto *CondBr = dyn_cast<CondBranchInst>(Latch->getTerminator());
if (!CondBr)
return None;
// Match an add 1 recurrence.
SILArgument *RecArg;
IntegerLiteralInst *End;
SILValue RecNext;
if (!match(CondBr->getCondition(),
m_BuiltinInst(BuiltinValueKind::ICMP_EQ, m_SILValue(RecNext),
m_IntegerLiteralInst(End))))
return None;
if (!match(RecNext,
m_TupleExtractInst(m_ApplyInst(BuiltinValueKind::SAddOver,
m_SILArgument(RecArg), m_One()),
0)))
return None;
if (RecArg->getParent() != Header)
return None;
auto *Start = dyn_cast_or_null<IntegerLiteralInst>(
RecArg->getIncomingValue(Preheader).getDef());
if (!Start)
return None;
if (RecNext != RecArg->getIncomingValue(OrigLatch))
return None;
auto StartVal = Start->getValue();
auto EndVal = End->getValue();
if (StartVal.sgt(EndVal))
return None;
auto Dist = EndVal - StartVal;
if (Dist.getBitWidth() > 64)
return None;
if (Dist == 0)
return None;
return Dist.getZExtValue();
}
/// \brief Issue diagnostics whenever we see Builtin.static_report(1, ...).
static void diagnoseStaticReports(const SILInstruction *I,
SILModule &M) {
// Find out if we are dealing with Builtin.staticReport().
if (auto *BI = dyn_cast<BuiltinInst>(I)) {
const BuiltinInfo &B = BI->getBuiltinInfo();
if (B.ID == BuiltinValueKind::StaticReport) {
// Report diagnostic if the first argument has been folded to '1'.
OperandValueArrayRef Args = BI->getArguments();
IntegerLiteralInst *V = dyn_cast<IntegerLiteralInst>(Args[0]);
if (!V || V->getValue() != 1)
return;
diagnose(M.getASTContext(), I->getLoc().getSourceLoc(),
diag::static_report_error);
}
}
}
