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[cast-opt] Eliminate always true if statement. #23086

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Merged
merged 1 commit into from
Mar 5, 2019
Merged

[cast-opt] Eliminate always true if statement. #23086

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78 changes: 38 additions & 40 deletions lib/SILOptimizer/Utils/CastOptimizer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -111,55 +111,53 @@ SILInstruction *CastOptimizer::optimizeBridgedObjCToSwiftCast(
Builder.setInsertionPoint(CurrInsPoint);
}

if (SILBridgedTy != Src->getType()) {
// Check if we can simplify a cast into:
// - ObjCTy to _ObjectiveCBridgeable._ObjectiveCType.
// - then convert _ObjectiveCBridgeable._ObjectiveCType to
// a Swift type using _forceBridgeFromObjectiveC.

if (!Src->getType().isLoadable(M)) {
// This code path is never reached in current test cases
// If reached, we'd have to convert from an ObjC Any* to a loadable type
// Should use check_addr / make a source we can actually load
return nullptr;
}
// We know this is always true since SILBridgedTy is an object and Src is an
// address.
assert(SILBridgedTy != Src->getType());

// Check if we can simplify a cast into:
// - ObjCTy to _ObjectiveCBridgeable._ObjectiveCType.
// - then convert _ObjectiveCBridgeable._ObjectiveCType to
// a Swift type using _forceBridgeFromObjectiveC.

if (!Src->getType().isLoadable(M)) {
// This code path is never reached in current test cases
// If reached, we'd have to convert from an ObjC Any* to a loadable type
// Should use check_addr / make a source we can actually load
return nullptr;
}

// Generate a load for the source argument.
auto *Load =
Builder.createLoad(Loc, Src, LoadOwnershipQualifier::Unqualified);
// Try to convert the source into the expected ObjC type first.
// Generate a load for the source argument.
auto *Load =
Builder.createLoad(Loc, Src, LoadOwnershipQualifier::Unqualified);
// Try to convert the source into the expected ObjC type first.

if (Load->getType() == SILBridgedTy) {
// If type of the source and the expected ObjC type are
// equal, there is no need to generate the conversion
// from ObjCTy to _ObjectiveCBridgeable._ObjectiveCType.
if (isConditional) {
SILBasicBlock *CastSuccessBB = F->createBasicBlock();
CastSuccessBB->createPhiArgument(SILBridgedTy,
ValueOwnershipKind::Owned);
Builder.createBranch(Loc, CastSuccessBB, SILValue(Load));
Builder.setInsertionPoint(CastSuccessBB);
SrcOp = CastSuccessBB->getArgument(0);
} else {
SrcOp = Load;
}
} else if (isConditional) {
if (Load->getType() == SILBridgedTy) {
// If type of the source and the expected ObjC type are
// equal, there is no need to generate the conversion
// from ObjCTy to _ObjectiveCBridgeable._ObjectiveCType.
if (isConditional) {
SILBasicBlock *CastSuccessBB = F->createBasicBlock();
CastSuccessBB->createPhiArgument(SILBridgedTy, ValueOwnershipKind::Owned);
auto *CCBI = Builder.createCheckedCastBranch(Loc, false, Load,
SILBridgedTy, CastSuccessBB, ConvFailBB);
NewI = CCBI;
splitEdge(CCBI, /* EdgeIdx to ConvFailBB */ 1);
Builder.createBranch(Loc, CastSuccessBB, SILValue(Load));
Builder.setInsertionPoint(CastSuccessBB);
SrcOp = CastSuccessBB->getArgument(0);
} else {
auto cast =
Builder.createUnconditionalCheckedCast(Loc, Load, SILBridgedTy);
NewI = cast;
SrcOp = cast;
SrcOp = Load;
}
} else if (isConditional) {
SILBasicBlock *CastSuccessBB = F->createBasicBlock();
CastSuccessBB->createPhiArgument(SILBridgedTy, ValueOwnershipKind::Owned);
auto *CCBI = Builder.createCheckedCastBranch(Loc, false, Load, SILBridgedTy,
CastSuccessBB, ConvFailBB);
NewI = CCBI;
splitEdge(CCBI, /* EdgeIdx to ConvFailBB */ 1);
Builder.setInsertionPoint(CastSuccessBB);
SrcOp = CastSuccessBB->getArgument(0);
} else {
SrcOp = Src;
auto cast = Builder.createUnconditionalCheckedCast(Loc, Load, SILBridgedTy);
NewI = cast;
SrcOp = cast;
}

// Now emit the a cast from the casted ObjC object into a target type.
Expand Down