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[cast-opt] Combine two blocks with the same condition and invert that condition to eliminate a level of indentation.

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NFCI.
This commit is contained in:
Michael Gottesman
2019-04-12 13:00:28 -07:00
parent 042b7420d5
commit b6611eee35
1 changed files with 64 additions and 54 deletions
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118
lib/SILOptimizer/Utils/CastOptimizer.cpp
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@@ -468,6 +468,61 @@ findBridgeToObjCFunc(SILOptFunctionBuilder &functionBuilder,
return std::make_pair(bridgedFunc, subMap);
}
static SILValue computeFinalCastedValue(SILBuilderWithScope &builder,
SILDynamicCastInst dynamicCast,
ApplyInst *newAI) {
SILValue dest = dynamicCast.getDest();
SILBasicBlock *failureBB = dynamicCast.getFailureBlock();
auto loc = dynamicCast.getLocation();
auto convTy = newAI->getType();
bool isConditional = dynamicCast.isConditional();
auto destTy = dest->getType().getObjectType();
assert(destTy == dynamicCast.getLoweredBridgedTargetObjectType() &&
"Expected Dest Type to be the same as BridgedTargetTy");
auto &m = dynamicCast.getModule();
if (convTy == destTy) {
return newAI;
}
if (destTy.isExactSuperclassOf(convTy)) {
return builder.createUpcast(loc, newAI, destTy);
}
if (convTy.isExactSuperclassOf(destTy)) {
// If we are not conditional, we are ok with the downcast via checked cast
// fails since we will trap.
if (!isConditional) {
return builder.createUnconditionalCheckedCast(loc, newAI, destTy);
}
// Otherwise if we /are/ emitting a conditional cast, make sure that we
// handle the failure gracefully.
auto *condBrSuccessBB =
newAI->getFunction()->createBasicBlockAfter(newAI->getParent());
condBrSuccessBB->createPhiArgument(destTy, ValueOwnershipKind::Owned,
nullptr);
builder.createCheckedCastBranch(loc, /* isExact*/ false, newAI, destTy,
condBrSuccessBB, failureBB);
builder.setInsertionPoint(condBrSuccessBB, condBrSuccessBB->begin());
return condBrSuccessBB->getArgument(0);
}
if (convTy.getASTType() ==
getNSBridgedClassOfCFClass(m.getSwiftModule(), destTy.getASTType()) ||
destTy.getASTType() ==
getNSBridgedClassOfCFClass(m.getSwiftModule(), convTy.getASTType())) {
// Handle NS <-> CF toll-free bridging here.
return SILValue(builder.createUncheckedRefCast(loc, newAI, destTy));
}
llvm_unreachable(
"optimizeBridgedSwiftToObjCCast: should never reach this condition: if "
"the Destination does not have the same type, is not a bridgeable CF "
"type and isn't a superclass/subclass of the source operand we should "
"have bailed earlier.");
}
/// Create a call of _bridgeToObjectiveC which converts an _ObjectiveCBridgeable
/// instance into a bridged ObjC type.
SILInstruction *
@@ -632,63 +687,18 @@ CastOptimizer::optimizeBridgedSwiftToObjCCast(SILDynamicCastInst dynamicCast) {
}
}
SILInstruction *NewI = NewAI;
if (!Dest)
return NewAI;
if (Dest) {
// If it is addr cast then store the result.
auto ConvTy = NewAI->getType();
auto DestTy = Dest->getType().getObjectType();
assert(DestTy == SILType::getPrimitiveObjectType(
BridgedTargetTy->getCanonicalType()) &&
"Expected Dest Type to be the same as BridgedTargetTy");
SILValue CastedValue;
if (ConvTy == DestTy) {
CastedValue = NewAI;
} else if (DestTy.isExactSuperclassOf(ConvTy)) {
CastedValue = Builder.createUpcast(Loc, NewAI, DestTy);
} else if (ConvTy.isExactSuperclassOf(DestTy)) {
// The downcast from a base class to derived class may fail.
if (isConditional) {
// In case of a conditional cast, we should handle it gracefully.
auto CondBrSuccessBB =
NewAI->getFunction()->createBasicBlockAfter(NewAI->getParent());
CondBrSuccessBB->createPhiArgument(DestTy, ValueOwnershipKind::Owned,
nullptr);
Builder.createCheckedCastBranch(Loc, /* isExact*/ false, NewAI, DestTy,
CondBrSuccessBB, FailureBB);
Builder.setInsertionPoint(CondBrSuccessBB, CondBrSuccessBB->begin());
CastedValue = CondBrSuccessBB->getArgument(0);
} else {
CastedValue = SILValue(
Builder.createUnconditionalCheckedCast(Loc, NewAI, DestTy));
}
} else if (ConvTy.getASTType() ==
getNSBridgedClassOfCFClass(M.getSwiftModule(),
DestTy.getASTType()) ||
DestTy.getASTType() ==
getNSBridgedClassOfCFClass(M.getSwiftModule(),
ConvTy.getASTType())) {
// Handle NS <-> CF toll-free bridging here.
CastedValue =
SILValue(Builder.createUncheckedRefCast(Loc, NewAI, DestTy));
} else {
llvm_unreachable("optimizeBridgedSwiftToObjCCast: should never reach "
"this condition: if the Destination does not have the "
"same type, is not a bridgeable CF type and isn't a "
"superclass/subclass of the source operand we should "
"have bailed earlier");
}
NewI = Builder.createStore(Loc, CastedValue, Dest,
StoreOwnershipQualifier::Unqualified);
if (isConditional && NewI->getParent() != NewAI->getParent()) {
Builder.createBranch(Loc, SuccessBB);
}
}
if (Dest) {
eraseInstAction(Inst);
// If it is addr cast then store the result.
SILValue castedValue = computeFinalCastedValue(Builder, dynamicCast, NewAI);
SILInstruction *NewI = Builder.createStore(
Loc, castedValue, Dest, StoreOwnershipQualifier::Unqualified);
if (isConditional && NewI->getParent() != NewAI->getParent()) {
Builder.createBranch(Loc, SuccessBB);
}
eraseInstAction(Inst);
return NewI;
}