1 //===- Matchers.h - Various common matchers ---------------------*- C++ -*-===//
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 // This file provides a simple and efficient mechanism for performing general
10 // tree-based pattern matching over MLIR. This mechanism is inspired by LLVM's
11 // include/llvm/IR/PatternMatch.h.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #ifndef MLIR_MATCHERS_H
16 #define MLIR_MATCHERS_H
17
18 #include "mlir/IR/BuiltinTypes.h"
19 #include "mlir/IR/OpDefinition.h"
20
21 namespace mlir {
22
23 namespace detail {
24
25 /// The matcher that matches a certain kind of Attribute and binds the value
26 /// inside the Attribute.
27 template <
28 typename AttrClass,
29 // Require AttrClass to be a derived class from Attribute and get its
30 // value type
31 typename ValueType =
32 typename std::enable_if<std::is_base_of<Attribute, AttrClass>::value,
33 AttrClass>::type::ValueType,
34 // Require the ValueType is not void
35 typename = typename std::enable_if<!std::is_void<ValueType>::value>::type>
36 struct attr_value_binder {
37 ValueType *bind_value;
38
39 /// Creates a matcher instance that binds the value to bv if match succeeds.
attr_value_binderattr_value_binder40 attr_value_binder(ValueType *bv) : bind_value(bv) {}
41
matchattr_value_binder42 bool match(const Attribute &attr) {
43 if (auto intAttr = attr.dyn_cast<AttrClass>()) {
44 *bind_value = intAttr.getValue();
45 return true;
46 }
47 return false;
48 }
49 };
50
51 /// The matcher that matches operations that have the `ConstantLike` trait.
52 struct constant_op_matcher {
matchconstant_op_matcher53 bool match(Operation *op) { return op->hasTrait<OpTrait::ConstantLike>(); }
54 };
55
56 /// The matcher that matches operations that have the `ConstantLike` trait, and
57 /// binds the folded attribute value.
58 template <typename AttrT> struct constant_op_binder {
59 AttrT *bind_value;
60
61 /// Creates a matcher instance that binds the constant attribute value to
62 /// bind_value if match succeeds.
constant_op_binderconstant_op_binder63 constant_op_binder(AttrT *bind_value) : bind_value(bind_value) {}
64 /// Creates a matcher instance that doesn't bind if match succeeds.
constant_op_binderconstant_op_binder65 constant_op_binder() : bind_value(nullptr) {}
66
matchconstant_op_binder67 bool match(Operation *op) {
68 if (!op->hasTrait<OpTrait::ConstantLike>())
69 return false;
70
71 // Fold the constant to an attribute.
72 SmallVector<OpFoldResult, 1> foldedOp;
73 LogicalResult result = op->fold(/*operands=*/llvm::None, foldedOp);
74 (void)result;
75 assert(succeeded(result) && "expected ConstantLike op to be foldable");
76
77 if (auto attr = foldedOp.front().get<Attribute>().dyn_cast<AttrT>()) {
78 if (bind_value)
79 *bind_value = attr;
80 return true;
81 }
82 return false;
83 }
84 };
85
86 /// The matcher that matches a constant scalar / vector splat / tensor splat
87 /// integer operation and binds the constant integer value.
88 struct constant_int_op_binder {
89 IntegerAttr::ValueType *bind_value;
90
91 /// Creates a matcher instance that binds the value to bv if match succeeds.
constant_int_op_binderconstant_int_op_binder92 constant_int_op_binder(IntegerAttr::ValueType *bv) : bind_value(bv) {}
93
matchconstant_int_op_binder94 bool match(Operation *op) {
95 Attribute attr;
96 if (!constant_op_binder<Attribute>(&attr).match(op))
97 return false;
98 auto type = op->getResult(0).getType();
99
100 if (type.isa<IntegerType, IndexType>())
101 return attr_value_binder<IntegerAttr>(bind_value).match(attr);
102 if (type.isa<VectorType, RankedTensorType>()) {
103 if (auto splatAttr = attr.dyn_cast<SplatElementsAttr>()) {
104 return attr_value_binder<IntegerAttr>(bind_value)
105 .match(splatAttr.getSplatValue());
106 }
107 }
108 return false;
109 }
110 };
111
112 /// The matcher that matches a given target constant scalar / vector splat /
113 /// tensor splat integer value.
114 template <int64_t TargetValue> struct constant_int_value_matcher {
matchconstant_int_value_matcher115 bool match(Operation *op) {
116 APInt value;
117 return constant_int_op_binder(&value).match(op) && TargetValue == value;
118 }
119 };
120
121 /// The matcher that matches anything except the given target constant scalar /
122 /// vector splat / tensor splat integer value.
123 template <int64_t TargetNotValue> struct constant_int_not_value_matcher {
matchconstant_int_not_value_matcher124 bool match(Operation *op) {
125 APInt value;
126 return constant_int_op_binder(&value).match(op) && TargetNotValue != value;
127 }
128 };
129
130 /// The matcher that matches a certain kind of op.
131 template <typename OpClass> struct op_matcher {
matchop_matcher132 bool match(Operation *op) { return isa<OpClass>(op); }
133 };
134
135 /// Trait to check whether T provides a 'match' method with type
136 /// `OperationOrValue`.
137 template <typename T, typename OperationOrValue>
138 using has_operation_or_value_matcher_t =
139 decltype(std::declval<T>().match(std::declval<OperationOrValue>()));
140
141 /// Statically switch to a Value matcher.
142 template <typename MatcherClass>
143 typename std::enable_if_t<
144 llvm::is_detected<detail::has_operation_or_value_matcher_t, MatcherClass,
145 Value>::value,
146 bool>
matchOperandOrValueAtIndex(Operation * op,unsigned idx,MatcherClass & matcher)147 matchOperandOrValueAtIndex(Operation *op, unsigned idx, MatcherClass &matcher) {
148 return matcher.match(op->getOperand(idx));
149 }
150
151 /// Statically switch to an Operation matcher.
152 template <typename MatcherClass>
153 typename std::enable_if_t<
154 llvm::is_detected<detail::has_operation_or_value_matcher_t, MatcherClass,
155 Operation *>::value,
156 bool>
matchOperandOrValueAtIndex(Operation * op,unsigned idx,MatcherClass & matcher)157 matchOperandOrValueAtIndex(Operation *op, unsigned idx, MatcherClass &matcher) {
158 if (auto defOp = op->getOperand(idx).getDefiningOp())
159 return matcher.match(defOp);
160 return false;
161 }
162
163 /// Terminal matcher, always returns true.
164 struct AnyValueMatcher {
matchAnyValueMatcher165 bool match(Value op) const { return true; }
166 };
167
168 /// Binds to a specific value and matches it.
169 struct PatternMatcherValue {
PatternMatcherValuePatternMatcherValue170 PatternMatcherValue(Value val) : value(val) {}
matchPatternMatcherValue171 bool match(Value val) const { return val == value; }
172 Value value;
173 };
174
175 template <typename TupleT, class CallbackT, std::size_t... Is>
enumerateImpl(TupleT && tuple,CallbackT && callback,std::index_sequence<Is...>)176 constexpr void enumerateImpl(TupleT &&tuple, CallbackT &&callback,
177 std::index_sequence<Is...>) {
178 (void)std::initializer_list<int>{
179 0,
180 (callback(std::integral_constant<std::size_t, Is>{}, std::get<Is>(tuple)),
181 0)...};
182 }
183
184 template <typename... Tys, typename CallbackT>
enumerate(std::tuple<Tys...> & tuple,CallbackT && callback)185 constexpr void enumerate(std::tuple<Tys...> &tuple, CallbackT &&callback) {
186 detail::enumerateImpl(tuple, std::forward<CallbackT>(callback),
187 std::make_index_sequence<sizeof...(Tys)>{});
188 }
189
190 /// RecursivePatternMatcher that composes.
191 template <typename OpType, typename... OperandMatchers>
192 struct RecursivePatternMatcher {
RecursivePatternMatcherRecursivePatternMatcher193 RecursivePatternMatcher(OperandMatchers... matchers)
194 : operandMatchers(matchers...) {}
matchRecursivePatternMatcher195 bool match(Operation *op) {
196 if (!isa<OpType>(op) || op->getNumOperands() != sizeof...(OperandMatchers))
197 return false;
198 bool res = true;
199 enumerate(operandMatchers, [&](size_t index, auto &matcher) {
200 res &= matchOperandOrValueAtIndex(op, index, matcher);
201 });
202 return res;
203 }
204 std::tuple<OperandMatchers...> operandMatchers;
205 };
206
207 } // end namespace detail
208
209 /// Matches a constant foldable operation.
m_Constant()210 inline detail::constant_op_matcher m_Constant() {
211 return detail::constant_op_matcher();
212 }
213
214 /// Matches a value from a constant foldable operation and writes the value to
215 /// bind_value.
216 template <typename AttrT>
m_Constant(AttrT * bind_value)217 inline detail::constant_op_binder<AttrT> m_Constant(AttrT *bind_value) {
218 return detail::constant_op_binder<AttrT>(bind_value);
219 }
220
221 /// Matches a constant scalar / vector splat / tensor splat integer one.
m_One()222 inline detail::constant_int_value_matcher<1> m_One() {
223 return detail::constant_int_value_matcher<1>();
224 }
225
226 /// Matches the given OpClass.
m_Op()227 template <typename OpClass> inline detail::op_matcher<OpClass> m_Op() {
228 return detail::op_matcher<OpClass>();
229 }
230
231 /// Matches a constant scalar / vector splat / tensor splat integer zero.
m_Zero()232 inline detail::constant_int_value_matcher<0> m_Zero() {
233 return detail::constant_int_value_matcher<0>();
234 }
235
236 /// Matches a constant scalar / vector splat / tensor splat integer that is any
237 /// non-zero value.
m_NonZero()238 inline detail::constant_int_not_value_matcher<0> m_NonZero() {
239 return detail::constant_int_not_value_matcher<0>();
240 }
241
242 /// Entry point for matching a pattern over a Value.
243 template <typename Pattern>
matchPattern(Value value,const Pattern & pattern)244 inline bool matchPattern(Value value, const Pattern &pattern) {
245 // TODO: handle other cases
246 if (auto *op = value.getDefiningOp())
247 return const_cast<Pattern &>(pattern).match(op);
248 return false;
249 }
250
251 /// Entry point for matching a pattern over an Operation.
252 template <typename Pattern>
matchPattern(Operation * op,const Pattern & pattern)253 inline bool matchPattern(Operation *op, const Pattern &pattern) {
254 return const_cast<Pattern &>(pattern).match(op);
255 }
256
257 /// Matches a constant holding a scalar/vector/tensor integer (splat) and
258 /// writes the integer value to bind_value.
259 inline detail::constant_int_op_binder
m_ConstantInt(IntegerAttr::ValueType * bind_value)260 m_ConstantInt(IntegerAttr::ValueType *bind_value) {
261 return detail::constant_int_op_binder(bind_value);
262 }
263
264 template <typename OpType, typename... Matchers>
m_Op(Matchers...matchers)265 auto m_Op(Matchers... matchers) {
266 return detail::RecursivePatternMatcher<OpType, Matchers...>(matchers...);
267 }
268
269 namespace matchers {
m_Any()270 inline auto m_Any() { return detail::AnyValueMatcher(); }
m_Val(Value v)271 inline auto m_Val(Value v) { return detail::PatternMatcherValue(v); }
272 } // namespace matchers
273
274 } // end namespace mlir
275
276 #endif // MLIR_MATCHERS_H
277