CIRCT  20.0.0git
Public Member Functions | Public Attributes | List of all members
circt::Reduction Struct Referenceabstract

An abstract reduction pattern. More...

#include <Reduction.h>

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Public Member Functions

virtual ~Reduction ()
 
virtual void beforeReduction (mlir::ModuleOp)
 Called before the reduction is applied to a new subset of operations. More...
 
virtual void afterReduction (mlir::ModuleOp)
 Called after the reduction has been applied to a subset of operations. More...
 
virtual uint64_t match (Operation *op)=0
 Check if the reduction can apply to a specific operation. More...
 
virtual LogicalResult rewrite (Operation *op)=0
 Apply the reduction to a specific operation. More...
 
virtual std::string getName () const =0
 Return a human-readable name for this reduction pattern. More...
 
virtual bool acceptSizeIncrease () const
 Return true if the tool should accept the transformation this reduction performs on the module even if the overall size of the output increases. More...
 
virtual bool isOneShot () const
 Return true if the tool should not try to reapply this reduction after it has been successful. More...
 
void notifyOpErased (Operation *op)
 

Public Attributes

std::function< void(Operation *)> notifyOpErasedCallback = nullptr
 An optional callback for reductions to communicate removal of operations. More...
 

Detailed Description

An abstract reduction pattern.

Definition at line 24 of file Reduction.h.

Constructor & Destructor Documentation

◆ ~Reduction()

Reduction::~Reduction ( )
virtualdefault

Member Function Documentation

◆ acceptSizeIncrease()

virtual bool circt::Reduction::acceptSizeIncrease ( ) const
inlinevirtual

Return true if the tool should accept the transformation this reduction performs on the module even if the overall size of the output increases.

This can be handy for patterns that reduce the complexity of the IR at the cost of some verbosity.

Reimplemented in ModuleNameSanitizer, ModuleInternalNameSanitizer, EagerInliner, ExtmoduleInstanceRemover, ConnectInvalidator, MemoryStubber, InstanceStubber, and circt::PassReduction.

Definition at line 55 of file Reduction.h.

◆ afterReduction()

virtual void circt::Reduction::afterReduction ( mlir::ModuleOp  )
inlinevirtual

Called after the reduction has been applied to a subset of operations.

Reductions may use this callback to perform post-processing of the reductions before the resulting module is tried for interestingness.

Reimplemented in EagerInliner, DetachSubaccesses, ConnectForwarder, ExtmoduleInstanceRemover, AnnotationRemover, MemoryStubber, InstanceStubber, and FIRRTLModuleExternalizer.

Definition at line 35 of file Reduction.h.

◆ beforeReduction()

virtual void circt::Reduction::beforeReduction ( mlir::ModuleOp  )
inlinevirtual

Called before the reduction is applied to a new subset of operations.

Reductions may use this callback to collect information such as symbol tables about the module upfront.

Reimplemented in ModuleInputPruner, ModuleOutputPruner< Front >, ModuleExternalizer, ModuleNameSanitizer, EagerInliner, DetachSubaccesses, ConnectForwarder, ExtmoduleInstanceRemover, AnnotationRemover, MemoryStubber, InstanceStubber, FIRRTLModuleExternalizer, and OperationPruner.

Definition at line 30 of file Reduction.h.

◆ getName()

virtual std::string circt::Reduction::getName ( ) const
pure virtual

◆ isOneShot()

virtual bool circt::Reduction::isOneShot ( ) const
inlinevirtual

Return true if the tool should not try to reapply this reduction after it has been successful.

This is useful for reductions whose match() function keeps returning true even after the reduction has reached a fixed-point and no longer performs any change. An example of this are reductions that apply a lowering pass which always applies but may leave the input unmodified.

This is mainly useful in conjunction with returning true from acceptSizeIncrease(). For reductions that don't accept an increase, the module size has to decrease for them to be considered useful, which prevents the tool from getting stuck at a local point where the reduction applies but produces no change in the input. However, reductions that do accept a size increase can get stuck in this local fixed-point as they keep applying to the same operations and the tool keeps accepting the unmodified input as an improvement.

Reimplemented in ModuleNameSanitizer, ModuleInternalNameSanitizer, and circt::PassReduction.

Definition at line 72 of file Reduction.h.

◆ match()

virtual uint64_t circt::Reduction::match ( Operation *  op)
pure virtual

◆ notifyOpErased()

void circt::Reduction::notifyOpErased ( Operation *  op)
inline

Definition at line 77 of file Reduction.h.

References notifyOpErasedCallback.

Referenced by circt::reduce::pruneUnusedOps().

◆ rewrite()

virtual LogicalResult circt::Reduction::rewrite ( Operation *  op)
pure virtual

Member Data Documentation

◆ notifyOpErasedCallback

std::function<void(Operation *)> circt::Reduction::notifyOpErasedCallback = nullptr

An optional callback for reductions to communicate removal of operations.

Definition at line 75 of file Reduction.h.

Referenced by notifyOpErased().


The documentation for this struct was generated from the following files: