Files
clang-p2996/mlir/lib/Transforms/Vectorization/VectorizerTestPass.cpp
Nicolas Vasilache d4921f4a96 Address Performance issue in NestedMatcher
A performance issue was reported due to the usage of NestedMatcher in
ComposeAffineMaps. The main culprit was the ubiquitous copies that were
occuring when appending even a single element in `matchOne`.

This CL generally simplifies the implementation and removes one level of indirection by getting rid of
auxiliary storage as well as simplifying the API.
The users of the API are updated accordingly.

The implementation was tested on a heavily unrolled example with
ComposeAffineMaps and is now close in performance with an implementation based
on stateless InstWalker.

As a reminder, the whole ComposeAffineMaps pass is slated to disappear but the bug report was very useful as a stress test for NestedMatchers.

Lastly, the following cleanups reported by @aminim were addressed:
1. make NestedPatternContext scoped within runFunction rather than at the Pass level. This was caused by a previous misunderstanding of Pass lifetime;
2. use defensive assertions in the constructor of NestedPatternContext to make it clear a unique such locally scoped context is allowed to exist.

PiperOrigin-RevId: 231781279
2019-03-29 16:04:07 -07:00

312 lines
10 KiB
C++

//===- VectorizerTestPass.cpp - VectorizerTestPass Pass Impl --------------===//
//
// Copyright 2019 The MLIR Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// =============================================================================
//
// This file implements a simple testing pass for vectorization functionality.
//
//===----------------------------------------------------------------------===//
#include "mlir/Analysis/AffineAnalysis.h"
#include "mlir/Analysis/NestedMatcher.h"
#include "mlir/Analysis/SliceAnalysis.h"
#include "mlir/Analysis/VectorAnalysis.h"
#include "mlir/IR/Builders.h"
#include "mlir/IR/BuiltinOps.h"
#include "mlir/IR/StandardTypes.h"
#include "mlir/Pass.h"
#include "mlir/Support/Functional.h"
#include "mlir/Support/STLExtras.h"
#include "mlir/Transforms/Passes.h"
#include "third_party/llvm/llvm/include/llvm/ADT/STLExtras.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#define DEBUG_TYPE "vectorizer-test"
using namespace mlir;
using llvm::outs;
using llvm::SetVector;
using functional::map;
static llvm::cl::OptionCategory clOptionsCategory(DEBUG_TYPE " options");
static llvm::cl::list<int> clTestVectorShapeRatio(
"vector-shape-ratio",
llvm::cl::desc("Specify the HW vector size for vectorization"),
llvm::cl::ZeroOrMore, llvm::cl::cat(clOptionsCategory));
static llvm::cl::opt<bool> clTestForwardSlicingAnalysis(
"forward-slicing",
llvm::cl::desc("Enable testing forward static slicing and topological sort "
"functionalities"),
llvm::cl::cat(clOptionsCategory));
static llvm::cl::opt<bool> clTestBackwardSlicingAnalysis(
"backward-slicing",
llvm::cl::desc("Enable testing backward static slicing and "
"topological sort functionalities"),
llvm::cl::cat(clOptionsCategory));
static llvm::cl::opt<bool> clTestSlicingAnalysis(
"slicing",
llvm::cl::desc("Enable testing static slicing and topological sort "
"functionalities"),
llvm::cl::cat(clOptionsCategory));
static llvm::cl::opt<bool> clTestComposeMaps(
"compose-maps",
llvm::cl::desc(
"Enable testing the composition of AffineMap where each "
"AffineMap in the composition is specified as the affine_map attribute "
"in a constant op."),
llvm::cl::cat(clOptionsCategory));
static llvm::cl::opt<bool> clTestNormalizeMaps(
"normalize-maps",
llvm::cl::desc(
"Enable testing the normalization of AffineAffineApplyOp "
"where each AffineAffineApplyOp in the composition is a single output "
"instruction."),
llvm::cl::cat(clOptionsCategory));
namespace {
struct VectorizerTestPass : public FunctionPass {
static constexpr auto kTestAffineMapOpName = "test_affine_map";
static constexpr auto kTestAffineMapAttrName = "affine_map";
VectorizerTestPass() : FunctionPass(&VectorizerTestPass::passID) {}
PassResult runOnFunction(Function *f) override;
void testVectorShapeRatio(Function *f);
void testForwardSlicing(Function *f);
void testBackwardSlicing(Function *f);
void testSlicing(Function *f);
void testComposeMaps(Function *f);
void testNormalizeMaps(Function *f);
static char passID;
};
} // end anonymous namespace
char VectorizerTestPass::passID = 0;
void VectorizerTestPass::testVectorShapeRatio(Function *f) {
using matcher::Op;
SmallVector<int64_t, 8> shape(clTestVectorShapeRatio.begin(),
clTestVectorShapeRatio.end());
auto subVectorType = VectorType::get(shape, Type::getF32(f->getContext()));
// Only filter instructions that operate on a strict super-vector and have one
// return. This makes testing easier.
auto filter = [subVectorType](const Instruction &inst) {
auto *opInst = dyn_cast<OperationInst>(&inst);
if (!opInst) {
return false;
}
assert(subVectorType.getElementType() ==
Type::getF32(subVectorType.getContext()) &&
"Only f32 supported for now");
if (!matcher::operatesOnSuperVectors(*opInst, subVectorType)) {
return false;
}
if (opInst->getNumResults() != 1) {
return false;
}
return true;
};
auto pat = Op(filter);
SmallVector<NestedMatch, 8> matches;
pat.match(f, &matches);
for (auto m : matches) {
auto *opInst = cast<OperationInst>(m.getMatchedInstruction());
// This is a unit test that only checks and prints shape ratio.
// As a consequence we write only Ops with a single return type for the
// purpose of this test. If we need to test more intricate behavior in the
// future we can always extend.
auto superVectorType = opInst->getResult(0)->getType().cast<VectorType>();
auto ratio = shapeRatio(superVectorType, subVectorType);
if (!ratio.hasValue()) {
opInst->emitNote("NOT MATCHED");
} else {
outs() << "\nmatched: " << *opInst << " with shape ratio: ";
interleaveComma(MutableArrayRef<unsigned>(*ratio), outs());
}
}
}
static std::string toString(Instruction *inst) {
std::string res;
auto os = llvm::raw_string_ostream(res);
inst->print(os);
return res;
}
static NestedPattern patternTestSlicingOps() {
// Just use a custom op name for this test, it makes life easier.
constexpr auto kTestSlicingOpName = "slicing-test-op";
using functional::map;
using matcher::Op;
// Match all OpInstructions with the kTestSlicingOpName name.
auto filter = [](const Instruction &inst) {
const auto &opInst = cast<OperationInst>(inst);
return opInst.getName().getStringRef() == kTestSlicingOpName;
};
return Op(filter);
}
void VectorizerTestPass::testBackwardSlicing(Function *f) {
SmallVector<NestedMatch, 8> matches;
patternTestSlicingOps().match(f, &matches);
for (auto m : matches) {
SetVector<Instruction *> backwardSlice;
getBackwardSlice(m.getMatchedInstruction(), &backwardSlice);
auto strs = map(toString, backwardSlice);
outs() << "\nmatched: " << *m.getMatchedInstruction()
<< " backward static slice: ";
for (const auto &s : strs) {
outs() << "\n" << s;
}
}
}
void VectorizerTestPass::testForwardSlicing(Function *f) {
SmallVector<NestedMatch, 8> matches;
patternTestSlicingOps().match(f, &matches);
for (auto m : matches) {
SetVector<Instruction *> forwardSlice;
getForwardSlice(m.getMatchedInstruction(), &forwardSlice);
auto strs = map(toString, forwardSlice);
outs() << "\nmatched: " << *m.getMatchedInstruction()
<< " forward static slice: ";
for (const auto &s : strs) {
outs() << "\n" << s;
}
}
}
void VectorizerTestPass::testSlicing(Function *f) {
SmallVector<NestedMatch, 8> matches;
patternTestSlicingOps().match(f, &matches);
for (auto m : matches) {
SetVector<Instruction *> staticSlice = getSlice(m.getMatchedInstruction());
auto strs = map(toString, staticSlice);
outs() << "\nmatched: " << *m.getMatchedInstruction() << " static slice: ";
for (const auto &s : strs) {
outs() << "\n" << s;
}
}
}
static bool customOpWithAffineMapAttribute(const Instruction &inst) {
const auto &opInst = cast<OperationInst>(inst);
return opInst.getName().getStringRef() ==
VectorizerTestPass::kTestAffineMapOpName;
}
void VectorizerTestPass::testComposeMaps(Function *f) {
using matcher::Op;
auto pattern = Op(customOpWithAffineMapAttribute);
SmallVector<NestedMatch, 8> matches;
pattern.match(f, &matches);
SmallVector<AffineMap, 4> maps;
maps.reserve(matches.size());
for (auto m : llvm::reverse(matches)) {
auto *opInst = cast<OperationInst>(m.getMatchedInstruction());
auto map = opInst->getAttr(VectorizerTestPass::kTestAffineMapAttrName)
.cast<AffineMapAttr>()
.getValue();
maps.push_back(map);
}
AffineMap res;
for (auto m : maps) {
res = res ? res.compose(m) : m;
}
simplifyAffineMap(res).print(outs() << "\nComposed map: ");
}
static bool affineApplyOp(const Instruction &inst) {
const auto &opInst = cast<OperationInst>(inst);
return opInst.isa<AffineApplyOp>();
}
static bool singleResultAffineApplyOpWithoutUses(const Instruction &inst) {
const auto &opInst = cast<OperationInst>(inst);
auto app = opInst.dyn_cast<AffineApplyOp>();
return app && app->use_empty();
}
void VectorizerTestPass::testNormalizeMaps(Function *f) {
using matcher::Op;
// Save matched AffineApplyOp that all need to be erased in the end.
auto pattern = Op(affineApplyOp);
SmallVector<NestedMatch, 8> toErase;
pattern.match(f, &toErase);
{
// Compose maps.
auto pattern = Op(singleResultAffineApplyOpWithoutUses);
SmallVector<NestedMatch, 8> matches;
pattern.match(f, &matches);
for (auto m : matches) {
auto app =
cast<OperationInst>(m.getMatchedInstruction())->cast<AffineApplyOp>();
FuncBuilder b(m.getMatchedInstruction());
SmallVector<Value *, 8> operands(app->getOperands());
makeComposedAffineApply(&b, app->getLoc(), app->getAffineMap(), operands);
}
}
// We should now be able to erase everything in reverse order in this test.
for (auto m : llvm::reverse(toErase)) {
m.getMatchedInstruction()->erase();
}
}
PassResult VectorizerTestPass::runOnFunction(Function *f) {
// Thread-safe RAII local context, BumpPtrAllocator freed on exit.
NestedPatternContext mlContext;
// Only support single block functions at this point.
if (f->getBlocks().size() != 1)
return success();
if (!clTestVectorShapeRatio.empty()) {
testVectorShapeRatio(f);
}
if (clTestForwardSlicingAnalysis) {
testForwardSlicing(f);
}
if (clTestBackwardSlicingAnalysis) {
testBackwardSlicing(f);
}
if (clTestSlicingAnalysis) {
testSlicing(f);
}
if (clTestComposeMaps) {
testComposeMaps(f);
}
if (clTestNormalizeMaps) {
testNormalizeMaps(f);
}
return PassResult::Success;
}
FunctionPass *mlir::createVectorizerTestPass() {
return new VectorizerTestPass();
}
static PassRegistration<VectorizerTestPass>
pass("vectorizer-test", "Tests vectorizer standalone functionality.");
#undef DEBUG_TYPE