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[rc-id] Enable RCIdentity analysis.

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Swift SVN r22006
This commit is contained in:
Michael Gottesman
2014-09-17 05:16:26 +00:00
parent 637f07f6f9
commit e47d5f574c
2 changed files with 1 additions and 125 deletions
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124
lib/SILAnalysis/RCIdentityAnalysis.cpp
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@@ -51,122 +51,6 @@ static bool isRCIdentityPreservingCast(ValueKind Kind) {
}
}
//===----------------------------------------------------------------------===//
// Old Code To Be Removed
//===----------------------------------------------------------------------===//
/// Return the underlying SILValue after stripping off identity SILArguments if
/// we belong to a BB with one predecessor.
static SILValue stripSinglePredecessorArgs(SILValue V) {
while (true) {
auto *A = dyn_cast<SILArgument>(V);
if (!A)
return V;
SILBasicBlock *BB = A->getParent();
// First try and grab the single predecessor of our parent BB. If we don't
// have one, bail.
SILBasicBlock *Pred = BB->getSinglePredecessor();
if (!Pred)
return V;
// Then grab the terminator of Pred...
TermInst *PredTI = Pred->getTerminator();
// And attempt to find our matching argument.
if (auto *BI = dyn_cast<BranchInst>(PredTI)) {
V = BI->getArg(A->getIndex());
continue;
}
if (auto *CBI = dyn_cast<CondBranchInst>(PredTI)) {
if (SILValue Arg = CBI->getArgForDestBB(BB, A)) {
V = Arg;
continue;
}
}
return V;
}
}
/// Return the underlying SILValue after stripping off SILArguments that can not
/// affect RC identity if our BB has only one predecessor.
static SILValue stripSinglePredecessorRCIdentityPreservingArgs(SILValue V) {
while (true) {
// First strip off non PHI args that
V = stripSinglePredecessorArgs(V);
auto *A = dyn_cast<SILArgument>(V);
if (!A)
return V;
SILBasicBlock *BB = A->getParent();
// First try and grab the single predecessor of our parent BB. If we don't
// have one, bail.
SILBasicBlock *Pred = BB->getSinglePredecessor();
if (!Pred)
return V;
// Then grab the terminator of Pred...
TermInst *PredTI = Pred->getTerminator();
if (auto *CCBI = dyn_cast<CheckedCastBranchInst>(PredTI)) {
V = CCBI->getOperand();
continue;
}
if (auto *SWEI = dyn_cast<SwitchEnumInst>(PredTI)) {
V = SWEI->getOperand();
continue;
}
return V;
}
}
static SILValue oldStripRCIdentityPreservingOps(SILValue V) {
while (true) {
V = stripSinglePredecessorRCIdentityPreservingArgs(V);
// Strip off RC identity preserving casts.
if (isRCIdentityPreservingCast(V->getKind())) {
V = cast<SILInstruction>(V.getDef())->getOperand(0);
continue;
}
// Then if we have a struct_extract that is extracting a non-trivial member
// from a struct with no other non-trivial members, a ref count operation on
// the struct is equivalent to a ref count operation on the extracted
// member. Strip off the extract.
if (auto *SEI = dyn_cast<StructExtractInst>(V)) {
if (SEI->isFieldOnlyNonTrivialField()) {
V = SEI->getOperand();
continue;
}
}
// If we have an unchecked_enum_data, strip off the unchecked_enum_data.
if (auto *UEDI = dyn_cast<UncheckedEnumDataInst>(V)) {
V = UEDI->getOperand();
continue;
}
// If we have an enum instruction with a payload, strip off the enum to
// expose the enum's payload.
if (auto *EI = dyn_cast<EnumInst>(V)) {
if (EI->hasOperand()) {
V = EI->getOperand();
continue;
}
}
return V;
}
}
//===----------------------------------------------------------------------===//
// Analysis
//===----------------------------------------------------------------------===//
@@ -347,15 +231,7 @@ SILValue RCIdentityAnalysis::getRCIdentityRootInner(SILValue V,
return Cache[V] = NewValue;
}
static llvm::cl::opt<bool>
EnableRCIdentityAnalysis("enable-rc-id-analysis", llvm::cl::init(false));
SILValue RCIdentityAnalysis::getRCIdentityRoot(SILValue V) {
// If the analysis is not enabled, just call the old SILValue method. We don't
// want this risk for OzU.
if (!EnableRCIdentityAnalysis)
return oldStripRCIdentityPreservingOps(V);
SILValue Root = getRCIdentityRootInner(V, 0);
VisitedArgs.clear();