Halide  19.0.0
Halide compiler and libraries
IRMutator.h
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1 #ifndef HALIDE_IR_MUTATOR_H
2 #define HALIDE_IR_MUTATOR_H
3 
4 /** \file
5  * Defines a base class for passes over the IR that modify it
6  */
7 
8 #include <map>
9 
10 #include "IR.h"
11 
12 namespace Halide {
13 namespace Internal {
14 
15 /** A base class for passes over the IR which modify it
16  * (e.g. replacing a variable with a value (Substitute.h), or
17  * constant-folding).
18  *
19  * Your mutator should override the visit() methods you care about and return
20  * the new expression or stmt. The default implementations recursively
21  * mutate their children. To mutate sub-expressions and sub-statements you
22  * should override the mutate() method, which will dispatch to
23  * the appropriate visit() method and then return the value of expr or
24  * stmt after the call to visit.
25  */
26 class IRMutator {
27 public:
28  IRMutator() = default;
29  virtual ~IRMutator() = default;
30 
31  /** This is the main interface for using a mutator. Also call
32  * these in your subclass to mutate sub-expressions and
33  * sub-statements.
34  */
35  virtual Expr mutate(const Expr &expr);
36  virtual Stmt mutate(const Stmt &stmt);
37 
38  // Mutate all the Exprs and return the new list in ret, along with
39  // a flag that is true iff at least one item in the list changed.
40  std::pair<std::vector<Expr>, bool> mutate_with_changes(const std::vector<Expr> &);
41 
42  // Like mutate_with_changes, but discard the changes flag.
43  std::vector<Expr> mutate(const std::vector<Expr> &exprs) {
44  return mutate_with_changes(exprs).first;
45  }
46 
47 protected:
48  // ExprNode<> and StmtNode<> are allowed to call visit (to implement mutate_expr/mutate_stmt())
49  template<typename T>
50  friend struct ExprNode;
51  template<typename T>
52  friend struct StmtNode;
53 
54  virtual Expr visit(const IntImm *);
55  virtual Expr visit(const UIntImm *);
56  virtual Expr visit(const FloatImm *);
57  virtual Expr visit(const StringImm *);
58  virtual Expr visit(const Cast *);
59  virtual Expr visit(const Reinterpret *);
60  virtual Expr visit(const Variable *);
61  virtual Expr visit(const Add *);
62  virtual Expr visit(const Sub *);
63  virtual Expr visit(const Mul *);
64  virtual Expr visit(const Div *);
65  virtual Expr visit(const Mod *);
66  virtual Expr visit(const Min *);
67  virtual Expr visit(const Max *);
68  virtual Expr visit(const EQ *);
69  virtual Expr visit(const NE *);
70  virtual Expr visit(const LT *);
71  virtual Expr visit(const LE *);
72  virtual Expr visit(const GT *);
73  virtual Expr visit(const GE *);
74  virtual Expr visit(const And *);
75  virtual Expr visit(const Or *);
76  virtual Expr visit(const Not *);
77  virtual Expr visit(const Select *);
78  virtual Expr visit(const Load *);
79  virtual Expr visit(const Ramp *);
80  virtual Expr visit(const Broadcast *);
81  virtual Expr visit(const Call *);
82  virtual Expr visit(const Let *);
83  virtual Expr visit(const Shuffle *);
84  virtual Expr visit(const VectorReduce *);
85 
86  virtual Stmt visit(const LetStmt *);
87  virtual Stmt visit(const AssertStmt *);
88  virtual Stmt visit(const ProducerConsumer *);
89  virtual Stmt visit(const For *);
90  virtual Stmt visit(const Store *);
91  virtual Stmt visit(const Provide *);
92  virtual Stmt visit(const Allocate *);
93  virtual Stmt visit(const Free *);
94  virtual Stmt visit(const Realize *);
95  virtual Stmt visit(const Block *);
96  virtual Stmt visit(const IfThenElse *);
97  virtual Stmt visit(const Evaluate *);
98  virtual Stmt visit(const Prefetch *);
99  virtual Stmt visit(const Acquire *);
100  virtual Stmt visit(const Fork *);
101  virtual Stmt visit(const Atomic *);
102  virtual Stmt visit(const HoistedStorage *);
103 };
104 
105 /** A mutator that caches and reapplies previously-done mutations, so
106  * that it can handle graphs of IR that have not had CSE done to
107  * them. */
108 class IRGraphMutator : public IRMutator {
109 protected:
110  std::map<Expr, Expr, ExprCompare> expr_replacements;
111  std::map<Stmt, Stmt, Stmt::Compare> stmt_replacements;
112 
113 public:
114  Stmt mutate(const Stmt &s) override;
115  Expr mutate(const Expr &e) override;
116 
117  std::vector<Expr> mutate(const std::vector<Expr> &exprs) {
118  return IRMutator::mutate(exprs);
119  }
120 };
121 
122 /** A helper function for mutator-like things to mutate regions */
123 template<typename Mutator, typename... Args>
124 std::pair<Region, bool> mutate_region(Mutator *mutator, const Region &bounds, Args &&...args) {
125  Region new_bounds(bounds.size());
126  bool bounds_changed = false;
127 
128  for (size_t i = 0; i < bounds.size(); i++) {
129  Expr old_min = bounds[i].min;
130  Expr old_extent = bounds[i].extent;
131  Expr new_min = mutator->mutate(old_min, std::forward<Args>(args)...);
132  Expr new_extent = mutator->mutate(old_extent, std::forward<Args>(args)...);
133  if (!new_min.same_as(old_min)) {
134  bounds_changed = true;
135  }
136  if (!new_extent.same_as(old_extent)) {
137  bounds_changed = true;
138  }
139  new_bounds[i] = Range(new_min, new_extent);
140  }
141  return {new_bounds, bounds_changed};
142 }
143 
144 } // namespace Internal
145 } // namespace Halide
146 
147 #endif
Subtypes for Halide expressions (Halide::Expr) and statements (Halide::Internal::Stmt)
A mutator that caches and reapplies previously-done mutations, so that it can handle graphs of IR tha...
Definition: IRMutator.h:108
std::vector< Expr > mutate(const std::vector< Expr > &exprs)
Definition: IRMutator.h:117
std::map< Expr, Expr, ExprCompare > expr_replacements
Definition: IRMutator.h:110
Expr mutate(const Expr &e) override
This is the main interface for using a mutator.
Stmt mutate(const Stmt &s) override
std::map< Stmt, Stmt, Stmt::Compare > stmt_replacements
Definition: IRMutator.h:111
A base class for passes over the IR which modify it (e.g.
Definition: IRMutator.h:26
virtual Stmt visit(const Free *)
virtual Expr visit(const Broadcast *)
virtual Expr visit(const VectorReduce *)
virtual Expr visit(const Call *)
virtual Stmt visit(const Atomic *)
virtual Expr visit(const Let *)
virtual Stmt visit(const Provide *)
virtual Expr visit(const Ramp *)
virtual Expr visit(const Mod *)
virtual Expr visit(const LE *)
virtual Expr visit(const Reinterpret *)
std::vector< Expr > mutate(const std::vector< Expr > &exprs)
Definition: IRMutator.h:43
virtual Stmt visit(const Store *)
virtual Expr visit(const Max *)
virtual Stmt visit(const HoistedStorage *)
virtual Expr visit(const Cast *)
virtual Stmt mutate(const Stmt &stmt)
virtual Stmt visit(const Block *)
virtual Expr visit(const Load *)
virtual Stmt visit(const Fork *)
virtual Stmt visit(const Allocate *)
std::pair< std::vector< Expr >, bool > mutate_with_changes(const std::vector< Expr > &)
virtual Stmt visit(const LetStmt *)
virtual Expr visit(const Or *)
virtual Expr visit(const And *)
virtual Stmt visit(const Acquire *)
virtual Stmt visit(const ProducerConsumer *)
virtual Expr visit(const Variable *)
virtual Expr visit(const Shuffle *)
virtual Expr visit(const LT *)
virtual Stmt visit(const For *)
virtual ~IRMutator()=default
virtual Expr visit(const Min *)
virtual Stmt visit(const AssertStmt *)
virtual Expr visit(const EQ *)
virtual Expr visit(const GT *)
virtual Expr visit(const Not *)
virtual Expr visit(const Add *)
virtual Expr visit(const NE *)
virtual Expr visit(const Div *)
virtual Expr visit(const Sub *)
virtual Stmt visit(const Evaluate *)
virtual Stmt visit(const Prefetch *)
virtual Stmt visit(const Realize *)
virtual Expr visit(const IntImm *)
virtual Expr mutate(const Expr &expr)
This is the main interface for using a mutator.
virtual Expr visit(const GE *)
virtual Expr visit(const UIntImm *)
virtual Stmt visit(const IfThenElse *)
virtual Expr visit(const FloatImm *)
virtual Expr visit(const Select *)
virtual Expr visit(const Mul *)
virtual Expr visit(const StringImm *)
std::pair< Region, bool > mutate_region(Mutator *mutator, const Region &bounds, Args &&...args)
A helper function for mutator-like things to mutate regions.
Definition: IRMutator.h:124
This file defines the class FunctionDAG, which is our representation of a Halide pipeline,...
@ Internal
Not visible externally, similar to 'static' linkage in C.
std::vector< Range > Region
A multi-dimensional box.
Definition: Expr.h:350
A fragment of Halide syntax.
Definition: Expr.h:258
The sum of two expressions.
Definition: IR.h:56
Allocate a scratch area called with the given name, type, and size.
Definition: IR.h:371
Logical and - are both expressions true.
Definition: IR.h:175
If the 'condition' is false, then evaluate and return the message, which should be a call to an error...
Definition: IR.h:294
Lock all the Store nodes in the body statement.
Definition: IR.h:954
A sequence of statements to be executed in-order.
Definition: IR.h:442
A vector with 'lanes' elements, in which every element is 'value'.
Definition: IR.h:259
A function call.
Definition: IR.h:490
The actual IR nodes begin here.
Definition: IR.h:30
The ratio of two expressions.
Definition: IR.h:83
Is the first expression equal to the second.
Definition: IR.h:121
Evaluate and discard an expression, presumably because it has some side-effect.
Definition: IR.h:476
We use the "curiously recurring template pattern" to avoid duplicated code in the IR Nodes.
Definition: Expr.h:158
Floating point constants.
Definition: Expr.h:236
A for loop.
Definition: IR.h:812
A pair of statements executed concurrently.
Definition: IR.h:457
Free the resources associated with the given buffer.
Definition: IR.h:413
Is the first expression greater than or equal to the second.
Definition: IR.h:166
Is the first expression greater than the second.
Definition: IR.h:157
Represents a location where storage will be hoisted to for a Func / Realize node with a given name.
Definition: IR.h:938
An if-then-else block.
Definition: IR.h:466
Integer constants.
Definition: Expr.h:218
HALIDE_ALWAYS_INLINE bool same_as(const IntrusivePtr &other) const
Definition: IntrusivePtr.h:171
Is the first expression less than or equal to the second.
Definition: IR.h:148
Is the first expression less than the second.
Definition: IR.h:139
A let expression, like you might find in a functional language.
Definition: IR.h:271
The statement form of a let node.
Definition: IR.h:282
Load a value from a named symbol if predicate is true.
Definition: IR.h:217
The greater of two values.
Definition: IR.h:112
The lesser of two values.
Definition: IR.h:103
The remainder of a / b.
Definition: IR.h:94
The product of two expressions.
Definition: IR.h:74
Is the first expression not equal to the second.
Definition: IR.h:130
Logical not - true if the expression false.
Definition: IR.h:193
Logical or - is at least one of the expression true.
Definition: IR.h:184
Represent a multi-dimensional region of a Func or an ImageParam that needs to be prefetched.
Definition: IR.h:916
This node is a helpful annotation to do with permissions.
Definition: IR.h:315
This defines the value of a function at a multi-dimensional location.
Definition: IR.h:354
A linear ramp vector node.
Definition: IR.h:247
Allocate a multi-dimensional buffer of the given type and size.
Definition: IR.h:427
Reinterpret value as another type, without affecting any of the bits (on little-endian systems).
Definition: IR.h:47
A ternary operator.
Definition: IR.h:204
Construct a new vector by taking elements from another sequence of vectors.
Definition: IR.h:848
A reference-counted handle to a statement node.
Definition: Expr.h:427
Store a 'value' to the buffer called 'name' at a given 'index' if 'predicate' is true.
Definition: IR.h:333
String constants.
Definition: Expr.h:245
The difference of two expressions.
Definition: IR.h:65
Unsigned integer constants.
Definition: Expr.h:227
A named variable.
Definition: IR.h:765
Horizontally reduce a vector to a scalar or narrower vector using the given commutative and associati...
Definition: IR.h:972
A single-dimensional span.
Definition: Expr.h:342