LLVM  11.0.0git
SSAUpdaterBulk.h
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1 //===- SSAUpdaterBulk.h - Unstructured SSA Update Tool ----------*- 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 declares the SSAUpdaterBulk class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H
14 #define LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H
15 
16 #include "llvm/ADT/DenseMap.h"
17 #include "llvm/ADT/StringRef.h"
19 
20 namespace llvm {
21 
22 class BasicBlock;
23 class PHINode;
24 template <typename T> class SmallVectorImpl;
25 class Type;
26 class Use;
27 class Value;
28 class DominatorTree;
29 
30 /// Helper class for SSA formation on a set of values defined in multiple
31 /// blocks.
32 ///
33 /// This is used when code duplication or another unstructured transformation
34 /// wants to rewrite a set of uses of one value with uses of a set of values.
35 /// The update is done only when RewriteAllUses is called, all other methods are
36 /// used for book-keeping. That helps to share some common computations between
37 /// updates of different uses (which is not the case when traditional SSAUpdater
38 /// is used).
40  struct RewriteInfo {
44  Type *Ty;
45  RewriteInfo(){};
46  RewriteInfo(StringRef &N, Type *T) : Name(N), Ty(T){};
47  };
49 
50  PredIteratorCache PredCache;
51 
52  Value *computeValueAt(BasicBlock *BB, RewriteInfo &R, DominatorTree *DT);
53 
54 public:
55  explicit SSAUpdaterBulk(){};
56  SSAUpdaterBulk(const SSAUpdaterBulk &) = delete;
57  SSAUpdaterBulk &operator=(const SSAUpdaterBulk &) = delete;
59 
60  /// Add a new variable to the SSA rewriter. This needs to be called before
61  /// AddAvailableValue or AddUse calls. The return value is the variable ID,
62  /// which needs to be passed to AddAvailableValue and AddUse.
63  unsigned AddVariable(StringRef Name, Type *Ty);
64 
65  /// Indicate that a rewritten value is available in the specified block with
66  /// the specified value.
67  void AddAvailableValue(unsigned Var, BasicBlock *BB, Value *V);
68 
69  /// Record a use of the symbolic value. This use will be updated with a
70  /// rewritten value when RewriteAllUses is called.
71  void AddUse(unsigned Var, Use *U);
72 
73  /// Return true if the SSAUpdater already has a value for the specified
74  /// variable in the specified block.
75  bool HasValueForBlock(unsigned Var, BasicBlock *BB);
76 
77  /// Perform all the necessary updates, including new PHI-nodes insertion and
78  /// the requested uses update.
79  ///
80  /// The function requires dominator tree DT, which is used for computing
81  /// locations for new phi-nodes insertions. If a nonnull pointer to a vector
82  /// InsertedPHIs is passed, all the new phi-nodes will be added to this
83  /// vector.
85  SmallVectorImpl<PHINode *> *InsertedPHIs = nullptr);
86 };
87 
88 } // end namespace llvm
89 
90 #endif // LLVM_TRANSFORMS_UTILS_SSAUPDATERBULK_H
This class represents lattice values for constants.
Definition: AllocatorList.h:23
Various leaf nodes.
Definition: ISDOpcodes.h:64
amdgpu Simplify well known AMD library false FunctionCallee Value const Twine & Name
unsigned AddVariable(StringRef Name, Type *Ty)
Add a new variable to the SSA rewriter.
A Use represents the edge between a Value definition and its users.
Definition: Use.h:44
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:43
void AddAvailableValue(unsigned Var, BasicBlock *BB, Value *V)
Indicate that a rewritten value is available in the specified block with the specified value...
PredIteratorCache - This class is an extremely trivial cache for predecessor iterator queries...
Helper class for SSA formation on a set of values defined in multiple blocks.
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree...
Definition: Dominators.h:144
LLVM Basic Block Representation.
Definition: BasicBlock.h:58
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
void AddUse(unsigned Var, Use *U)
Record a use of the symbolic value.
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:883
void RewriteAllUses(DominatorTree *DT, SmallVectorImpl< PHINode *> *InsertedPHIs=nullptr)
Perform all the necessary updates, including new PHI-nodes insertion and the requested uses update...
#define N
LLVM Value Representation.
Definition: Value.h:74
SSAUpdaterBulk & operator=(const SSAUpdaterBulk &)=delete
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:57
bool HasValueForBlock(unsigned Var, BasicBlock *BB)
Return true if the SSAUpdater already has a value for the specified variable in the specified block...