308571074c
This is an artifact from merging MLIR into LLVM, the file headers are now aligned with the rest of the project.
113 lines
3.9 KiB
C++
113 lines
3.9 KiB
C++
//===- ConvertConst.cpp - Quantizes constant ops --------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "mlir/Dialect/QuantOps/Passes.h"
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#include "mlir/Dialect/QuantOps/QuantOps.h"
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#include "mlir/Dialect/QuantOps/QuantizeUtils.h"
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#include "mlir/Dialect/QuantOps/UniformSupport.h"
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#include "mlir/Dialect/StandardOps/Ops.h"
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#include "mlir/IR/Attributes.h"
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#include "mlir/IR/Matchers.h"
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#include "mlir/IR/PatternMatch.h"
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#include "mlir/IR/StandardTypes.h"
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#include "mlir/Pass/Pass.h"
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using namespace mlir;
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using namespace mlir::quant;
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namespace {
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class ConvertConstPass : public FunctionPass<ConvertConstPass> {
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public:
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void runOnFunction() override;
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};
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struct QuantizedConstRewrite : public OpRewritePattern<QuantizeCastOp> {
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using OpRewritePattern<QuantizeCastOp>::OpRewritePattern;
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PatternMatchResult matchAndRewrite(QuantizeCastOp qbarrier,
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PatternRewriter &rewriter) const override;
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};
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} // end anonymous namespace
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/// Matches a [constant] -> [qbarrier] where the qbarrier results type is
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/// quantized and the operand type is quantizable.
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PatternMatchResult
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QuantizedConstRewrite::matchAndRewrite(QuantizeCastOp qbarrier,
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PatternRewriter &rewriter) const {
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Attribute value;
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// Is the operand a constant?
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if (!matchPattern(qbarrier.arg(), m_Constant(&value))) {
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return matchFailure();
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}
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// Does the qbarrier convert to a quantized type. This will not be true
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// if a quantized type has not yet been chosen or if the cast to an equivalent
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// storage type is not supported.
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Type qbarrierResultType = qbarrier.getResult().getType();
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QuantizedType quantizedElementType =
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QuantizedType::getQuantizedElementType(qbarrierResultType);
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if (!quantizedElementType) {
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return matchFailure();
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}
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if (!QuantizedType::castToStorageType(qbarrierResultType)) {
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return matchFailure();
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}
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// Is the operand type compatible with the expressed type of the quantized
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// type? This will not be true if the qbarrier is superfluous (converts
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// from and to a quantized type).
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if (!quantizedElementType.isCompatibleExpressedType(
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qbarrier.arg().getType())) {
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return matchFailure();
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}
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// Is the constant value a type expressed in a way that we support?
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if (!value.isa<FloatAttr>() && !value.isa<DenseElementsAttr>() &&
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!value.isa<SparseElementsAttr>()) {
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return matchFailure();
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}
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Type newConstValueType;
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auto newConstValue =
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quantizeAttr(value, quantizedElementType, newConstValueType);
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if (!newConstValue) {
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return matchFailure();
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}
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// When creating the new const op, use a fused location that combines the
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// original const and the qbarrier that led to the quantization.
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auto fusedLoc = FusedLoc::get(
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{qbarrier.arg().getDefiningOp()->getLoc(), qbarrier.getLoc()},
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rewriter.getContext());
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auto newConstOp =
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rewriter.create<ConstantOp>(fusedLoc, newConstValueType, newConstValue);
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rewriter.replaceOpWithNewOp<StorageCastOp>({qbarrier.arg()}, qbarrier,
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qbarrier.getType(), newConstOp);
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return matchSuccess();
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}
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void ConvertConstPass::runOnFunction() {
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OwningRewritePatternList patterns;
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auto func = getFunction();
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auto *context = &getContext();
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patterns.insert<QuantizedConstRewrite>(context);
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applyPatternsGreedily(func, patterns);
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}
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std::unique_ptr<OpPassBase<FuncOp>> mlir::quant::createConvertConstPass() {
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return std::make_unique<ConvertConstPass>();
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}
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static PassRegistration<ConvertConstPass>
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pass("quant-convert-const",
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"Converts constants followed by qbarrier to actual quantized values");
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