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[ome] Eliminate inefficiencies in lowering of destructures to ensure -Onone output stays the same. #22506

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Merged
merged 2 commits into from
Feb 11, 2019
Merged

[ome] Eliminate inefficiencies in lowering of destructures to ensure -Onone output stays the same. #22506

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cec2b98
[ownership] When transforming destructures => projections, only creat…
gottesmm Feb 1, 2019
89a447a
[ownership] When splitting destructures, simplify the instruction if …
gottesmm Feb 11, 2019
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38 changes: 30 additions & 8 deletions lib/SILOptimizer/Transforms/OwnershipModelEliminator.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,9 @@
#include "swift/SIL/SILBuilder.h"
#include "swift/SIL/SILFunction.h"
#include "swift/SIL/SILVisitor.h"
#include "swift/SILOptimizer/Analysis/SimplifyInstruction.h"
#include "swift/SILOptimizer/PassManager/Transforms.h"
#include "swift/SILOptimizer/Utils/Local.h"
#include "llvm/Support/CommandLine.h"

using namespace swift;
Expand Down Expand Up @@ -248,6 +250,9 @@ static void splitDestructure(SILBuilder &B, SILInstruction *I, SILValue Op) {
assert((isa<DestructureStructInst>(I) || isa<DestructureTupleInst>(I)) &&
"Only destructure operations can be passed to splitDestructure");

// First before we destructure anything, see if we can simplify any of our
// instruction operands.

SILModule &M = I->getModule();
SILLocation Loc = I->getLoc();
SILType OpType = Op->getType();
Expand All @@ -256,16 +261,33 @@ static void splitDestructure(SILBuilder &B, SILInstruction *I, SILValue Op) {
Projection::getFirstLevelProjections(OpType, M, Projections);
assert(Projections.size() == I->getNumResults());

llvm::SmallVector<SILValue, 8> NewValues;
for (unsigned i : indices(Projections)) {
const auto &Proj = Projections[i];
NewValues.push_back(Proj.createObjectProjection(B, Loc, Op).get());
assert(NewValues.back()->getType() == I->getResults()[i]->getType() &&
"Expected created projections and results to be the same types");
auto Results = I->getResults();
for (unsigned Index : indices(Results)) {
SILValue Result = Results[Index];

// If our result doesnt have any uses, do not emit instructions, just skip
// it.
if (Result->use_empty())
continue;

// Otherwise, create a projection.
const auto &Proj = Projections[Index];
SingleValueInstruction *ProjInst =
Proj.createObjectProjection(B, Loc, Op).get();

// If we can simplify, do so.
if (SILValue NewV = simplifyInstruction(ProjInst)) {
Result->replaceAllUsesWith(NewV);
ProjInst->eraseFromParent();
continue;
}

Result->replaceAllUsesWith(ProjInst);
}

I->replaceAllUsesPairwiseWith(NewValues);
I->eraseFromParent();
// We may have exposed trivially dead instructions due to
// simplifyInstruction... delete I and any such instructions!
recursivelyDeleteTriviallyDeadInstructions(I, true);
}

bool OwnershipModelEliminatorVisitor::visitDestructureStructInst(
Expand Down
30 changes: 30 additions & 0 deletions test/SILOptimizer/ownership_model_eliminator.sil
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Expand Up @@ -299,3 +299,33 @@ bb0(%0 : @owned $(Builtin.NativeObject, Builtin.Int32), %1 : @owned $TestArray2)
%7 = tuple(%2 : $Builtin.NativeObject, %3 : $Builtin.Int32, %4 : $TestArrayStorage, %5 : $Builtin.Int32, %6 : $TestArrayStorage)
return %7 : $(Builtin.NativeObject, Builtin.Int32, TestArrayStorage, Builtin.Int32, TestArrayStorage)
}

// In the following test, the trivial parts do not have any actual uses... do
// not emit any value projections for them!
//
// CHECK-LABEL: sil [canonical] @test_destructure_with_only_some_uses : $@convention(thin) (@owned (Builtin.NativeObject, Builtin.Int32), @owned TestArray2) -> @owned (Builtin.NativeObject, TestArrayStorage, TestArrayStorage) {
// CHECK: bb0([[ARG0:%.*]] : $(Builtin.NativeObject, Builtin.Int32), [[ARG1:%.*]] : $TestArray2):
// CHECK-NEXT: [[ARG0_0:%.*]] = tuple_extract [[ARG0]]
// CHECK-NEXT: [[STORAGE:%.*]] = struct_extract [[ARG1]] : $TestArray2, #TestArray2.storage
// CHECK-NEXT: [[STORAGE2:%.*]] = struct_extract [[ARG1]] : $TestArray2, #TestArray2.storage2
// CHECK-NEXT: [[RESULT:%.*]] = tuple ([[ARG0_0]] : ${{.*}}, [[STORAGE]] : ${{.*}}, [[STORAGE2]] : ${{.*}})
// CHECK-NEXT: return [[RESULT]]
// CHECK: } // end sil function 'test_destructure_with_only_some_uses'
sil [canonical] [ossa] @test_destructure_with_only_some_uses : $@convention(thin) (@owned (Builtin.NativeObject, Builtin.Int32), @owned TestArray2) -> @owned (Builtin.NativeObject, TestArrayStorage, TestArrayStorage) {
bb0(%0 : @owned $(Builtin.NativeObject, Builtin.Int32), %1 : @owned $TestArray2):
(%2, %3) = destructure_tuple %0 : $(Builtin.NativeObject, Builtin.Int32)
(%4, %5, %6) = destructure_struct %1 : $TestArray2
%7 = tuple (%2 : $Builtin.NativeObject, %4 : $TestArrayStorage, %6 : $TestArrayStorage)
return %7 : $(Builtin.NativeObject, TestArrayStorage, TestArrayStorage)
}

// CHECK-LABEL: sil [canonical] @test_simplify_instruction : $@convention(thin) (@owned Builtin.NativeObject, Builtin.Int32) -> @owned Builtin.NativeObject {
// CHECK: bb0([[ARG:%.*]] : $Builtin.NativeObject,
// CHECK-NEXT: return [[ARG]]
// CHECK: } // end sil function 'test_simplify_instruction'
sil [canonical] [ossa] @test_simplify_instruction : $@convention(thin) (@owned Builtin.NativeObject, Builtin.Int32) -> @owned Builtin.NativeObject {
bb0(%0 : @owned $Builtin.NativeObject, %1 : $Builtin.Int32):
%2 = tuple(%0 : $Builtin.NativeObject, %1 : $Builtin.Int32)
(%3, %4) = destructure_tuple %2 : $(Builtin.NativeObject, Builtin.Int32)
return %3 : $Builtin.NativeObject
}
18 changes: 11 additions & 7 deletions test/Serialization/transparent-std.swift
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Expand Up @@ -16,13 +16,17 @@ func test_foo(x: Builtin.Int1, y: Builtin.Int1) -> Builtin.Int1 {
}

// SIL-LABEL: sil public_external [transparent] [serialized] [canonical] @$s19def_transparent_std12assign_tuple1x1yyBi64__Bot_BptF : $@convention(thin) (Builtin.Int64, @guaranteed Builtin.NativeObject, Builtin.RawPointer) -> () {
// SIL: = tuple (%0 : $Builtin.Int64, %1 : $Builtin.NativeObject)
// SIL: retain_value
// SIL: = tuple_extract
// SIL: = tuple_extract
// SIL: = pointer_to_address
// SIL: = tuple
// SIL: = load
// SIL: bb0([[ARG0:%.*]] : ${{.*}}, [[ARG1:%.*]] : ${{.*}}, [[ARG2:%.*]] :
// SIL: [[TUP:%.*]] = tuple ([[ARG0]] : $Builtin.Int64, [[ARG1]] : $Builtin.NativeObject)
// SIL: retain_value [[TUP]]
// SIL: [[CASTED_PTR:%.*]] = pointer_to_address [[ARG2]]
// SIL: [[CASTED_PTR_0:%.*]] = tuple_element_addr [[CASTED_PTR]] : $*(Builtin.Int64, Builtin.NativeObject), 0
// SIL: store [[ARG0]] to [[CASTED_PTR_0]]
// SIL: [[CASTED_PTR_1:%.*]] = tuple_element_addr [[CASTED_PTR]] : $*(Builtin.Int64, Builtin.NativeObject), 1
// SIL: [[OLD_VALUE:%.*]] = load [[CASTED_PTR_1]]
// SIL: store [[ARG1]] to [[CASTED_PTR_1]]
// SIL: strong_release [[OLD_VALUE]]
// SIL: } // end sil function '$s19def_transparent_std12assign_tuple1x1yyBi64__Bot_BptF'
func test_tuple(x: (Builtin.Int64, Builtin.NativeObject),
y: Builtin.RawPointer) {
assign_tuple(x: x, y: y)
Expand Down