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[IRGen] Optimize Builtin.arrayDestroy when count is 1 #72636

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Merged
merged 2 commits into from
Mar 28, 2024
Merged

[IRGen] Optimize Builtin.arrayDestroy when count is 1 #72636

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48ec9c6
Optimize Builtin.destroyArray when count is 1 statically
Azoy Mar 27, 2024
8ea3426
Update comment about arrayDestroy in pointer
Azoy Mar 27, 2024
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11 changes: 11 additions & 0 deletions lib/IRGen/GenBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1137,6 +1137,17 @@ void irgen::emitBuiltinCall(IRGenFunction &IGF, const BuiltinInfo &Builtin,
ptr = IGF.Builder.CreateBitCast(ptr,
valueTy.second.getStorageType()->getPointerTo());
Address array = valueTy.second.getAddressForPointer(ptr);

// If the count is statically known to be a constant 1, then just call the
// type's destroy instead of the array variant.
if (auto ci = dyn_cast<llvm::ConstantInt>(count)) {
if (ci->isOne()) {
bool isOutlined = false;
valueTy.second.destroy(IGF, array, valueTy.first, isOutlined);
return;
}
}

valueTy.second.destroyArray(IGF, array, count, valueTy.first);
return;
}
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4 changes: 2 additions & 2 deletions stdlib/public/core/UnsafePointer.swift
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Expand Up @@ -1166,8 +1166,8 @@ extension UnsafeMutablePointer where Pointee: ~Copyable {
@discardableResult
public func deinitialize(count: Int) -> UnsafeMutableRawPointer {
_debugPrecondition(count >= 0, "UnsafeMutablePointer.deinitialize with negative count")
// TODO: IRGen optimization when `count` value is statically known to be 1,
// then call `Builtin.destroy(Pointee.self, _rawValue)` instead.
// Note: When count is statically known to be 1 the compiler will optimize
// away a call to swift_arrayDestroy into the type's specific destroy.
Builtin.destroyArray(Pointee.self, _rawValue, count._builtinWordValue)
return UnsafeMutableRawPointer(self)
}
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20 changes: 20 additions & 0 deletions test/IRGen/builtins.swift
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Expand Up @@ -456,6 +456,26 @@ func destroyGenArray<T>(_ array: Builtin.RawPointer, count: Builtin.Word, _: T)
Builtin.destroyArray(T.self, array, count)
}

// CHECK-LABEL: define hidden {{.*}}void @"$s8builtins21destroyArraySinglePODyyBpF"(ptr %0)
// CHECK-NOT: call void @swift_arrayDestroy
func destroyArraySinglePOD(_ array: Builtin.RawPointer) {
Builtin.destroyArray(Int.self, array, 1._builtinWordValue)
}

// CHECK-LABEL: define hidden {{.*}}void @"$s8builtins24destroyArraySingleNonPODyyBpF"(ptr %0)
// CHECK-NOT: call void @swift_arrayDestroy
// CHECK: [[TO_DESTROY:%.*]] = load ptr, ptr {{%.*}}
// CHECK: call void @swift_release(ptr [[TO_DESTROY]])
func destroyArraySingleNonPOD(_ array: Builtin.RawPointer) {
Builtin.destroyArray(C.self, array, 1._builtinWordValue)
}

// CHECK-LABEL: define hidden {{.*}}void @"$s8builtins21destroyArraySingleGenyyBp_xmtlF"(ptr %0, ptr %1, ptr %T)
// CHECK-NOT: call void @swift_arrayDestroy
// CHECK: call void {{%.*}}(ptr {{.*}} {{%.*}}, ptr %T)
func destroyArraySingleGen<T>(_ array: Builtin.RawPointer, _: T.Type) {
Builtin.destroyArray(T.self, array, 1._builtinWordValue)
}

// CHECK-LABEL: define hidden {{.*}}void @"$s8builtins12copyPODArray{{[_0-9a-zA-Z]*}}F"(ptr %0, ptr %1, i64 %2)
// check: mul nuw i64 4, %2
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