1 //===- ConvertSimQuant.cpp - Converts simulated quant ops------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "PassDetail.h"
10 #include "mlir/Dialect/Quant/FakeQuantSupport.h"
11 #include "mlir/Dialect/Quant/Passes.h"
12 #include "mlir/Dialect/Quant/QuantOps.h"
13 #include "mlir/Dialect/Quant/UniformSupport.h"
14 #include "mlir/IR/BuiltinTypes.h"
15 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
16
17 using namespace mlir;
18 using namespace mlir::quant;
19
20 namespace {
21 struct ConvertSimulatedQuantPass
22 : public QuantConvertSimulatedQuantBase<ConvertSimulatedQuantPass> {
23 void runOnFunction() override;
24 };
25
26 /// Base class rewrites ConstFakeQuant into a qbarrier/dbarrier pair.
27 template <typename ConcreteRewriteClass, typename FakeQuantOp>
28 class FakeQuantRewrite : public OpRewritePattern<FakeQuantOp> {
29 public:
30 using OpRewritePattern<FakeQuantOp>::OpRewritePattern;
31
FakeQuantRewrite(MLIRContext * ctx,bool * hadFailure)32 FakeQuantRewrite(MLIRContext *ctx, bool *hadFailure)
33 : OpRewritePattern<FakeQuantOp>(ctx), hadFailure(hadFailure) {}
34
matchAndRewrite(FakeQuantOp op,PatternRewriter & rewriter) const35 LogicalResult matchAndRewrite(FakeQuantOp op,
36 PatternRewriter &rewriter) const override {
37 // TODO: If this pattern comes up more frequently, consider adding core
38 // support for failable rewrites.
39 if (failableRewrite(op, rewriter)) {
40 *hadFailure = true;
41 return failure();
42 }
43
44 return success();
45 }
46
47 private:
48 bool *hadFailure;
49
failableRewrite(FakeQuantOp op,PatternRewriter & rewriter) const50 bool failableRewrite(FakeQuantOp op, PatternRewriter &rewriter) const {
51 auto converter = ExpressedToQuantizedConverter::forInputType(op.getType());
52 if (!converter) {
53 return (op.emitError("unsupported quantized type conversion"), true);
54 }
55
56 QuantizedType elementType =
57 static_cast<const ConcreteRewriteClass *>(this)
58 ->convertFakeQuantAttrsToType(op, converter.expressedType);
59
60 if (!elementType) {
61 // Note that the fakeQuantAttrsToType will have emitted the error.
62 return true;
63 }
64
65 Type quantizedType = converter.convert(elementType);
66 assert(quantizedType &&
67 "Converter accepted a type that it did not convert");
68
69 // TODO: Map to a qbarrier with an attribute like [Forced] to signal that
70 // this is a forced/hard-coded constraint.
71 auto qbarrier = rewriter.create<QuantizeCastOp>(op.getLoc(), quantizedType,
72 op.inputs());
73 rewriter.replaceOpWithNewOp<DequantizeCastOp>(op, converter.inputType,
74 qbarrier.getResult());
75
76 return false;
77 }
78 };
79
80 class ConstFakeQuantRewrite
81 : public FakeQuantRewrite<ConstFakeQuantRewrite, ConstFakeQuant> {
82 public:
83 using BaseRewrite = FakeQuantRewrite<ConstFakeQuantRewrite, ConstFakeQuant>;
84
ConstFakeQuantRewrite(MLIRContext * ctx,bool * hadFailure)85 ConstFakeQuantRewrite(MLIRContext *ctx, bool *hadFailure)
86 : BaseRewrite(ctx, hadFailure) {}
87
convertFakeQuantAttrsToType(ConstFakeQuant fqOp,Type expressedType) const88 QuantizedType convertFakeQuantAttrsToType(ConstFakeQuant fqOp,
89 Type expressedType) const {
90 return fakeQuantAttrsToType(
91 fqOp.getLoc(), fqOp.num_bits(), fqOp.min().convertToFloat(),
92 fqOp.max().convertToFloat(), fqOp.narrow_range(), expressedType,
93 fqOp.is_signed());
94 }
95 };
96
97 class ConstFakeQuantPerAxisRewrite
98 : public FakeQuantRewrite<ConstFakeQuantPerAxisRewrite,
99 ConstFakeQuantPerAxis> {
100 public:
101 using BaseRewrite =
102 FakeQuantRewrite<ConstFakeQuantPerAxisRewrite, ConstFakeQuantPerAxis>;
103
ConstFakeQuantPerAxisRewrite(MLIRContext * ctx,bool * hadFailure)104 ConstFakeQuantPerAxisRewrite(MLIRContext *ctx, bool *hadFailure)
105 : BaseRewrite(ctx, hadFailure) {}
106
convertFakeQuantAttrsToType(ConstFakeQuantPerAxis fqOp,Type expressedType) const107 QuantizedType convertFakeQuantAttrsToType(ConstFakeQuantPerAxis fqOp,
108 Type expressedType) const {
109 SmallVector<double, 4> min, max;
110 min.reserve(fqOp.min().size());
111 max.reserve(fqOp.max().size());
112 for (auto m : fqOp.min())
113 min.push_back(m.cast<FloatAttr>().getValueAsDouble());
114 for (auto m : fqOp.max())
115 max.push_back(m.cast<FloatAttr>().getValueAsDouble());
116
117 return fakeQuantAttrsToType(fqOp.getLoc(), fqOp.num_bits(), fqOp.axis(),
118 min, max, fqOp.narrow_range(), expressedType,
119 fqOp.is_signed());
120 }
121 };
122
123 } // namespace
124
runOnFunction()125 void ConvertSimulatedQuantPass::runOnFunction() {
126 bool hadFailure = false;
127 auto func = getFunction();
128 RewritePatternSet patterns(func.getContext());
129 auto ctx = func.getContext();
130 patterns.add<ConstFakeQuantRewrite, ConstFakeQuantPerAxisRewrite>(
131 ctx, &hadFailure);
132 (void)applyPatternsAndFoldGreedily(func, std::move(patterns));
133 if (hadFailure)
134 signalPassFailure();
135 }
136
137 std::unique_ptr<OperationPass<FuncOp>>
createConvertSimulatedQuantPass()138 mlir::quant::createConvertSimulatedQuantPass() {
139 return std::make_unique<ConvertSimulatedQuantPass>();
140 }
141