mlir::VectorTransferToSCFOptions Struct Reference

When lowering an N-d vector transfer op to an (N-1)-d vector transfer op, a temporary buffer is created through which individual (N-1)-d vector are staged. More...

#include "mlir/Conversion/VectorToSCF/VectorToSCF.h"

Public Member Functions
VectorTransferToSCFOptions &	setTargetRank (unsigned r)
VectorTransferToSCFOptions &	enableLowerTensors (bool l=true)
VectorTransferToSCFOptions &	enableFullUnroll (bool u=true)
VectorTransferToSCFOptions	enableLowerScalable (bool enable=true)

Public Attributes
unsigned	targetRank = 1
	Minimal rank to which vector transfer are lowered. More...
bool	lowerTensors = false
	Allows vector transfers that operated on tensors to be lowered (this is an uncommon alternative). More...
bool	unroll = false
	Triggers full unrolling (vs iterating with a loop) during transfer to scf. More...
bool	lowerScalable = false
	Enable scalable vector specific lowerings (which introduce loops). More...

Detailed Description

When lowering an N-d vector transfer op to an (N-1)-d vector transfer op, a temporary buffer is created through which individual (N-1)-d vector are staged.

This pattern can be applied multiple time, until the transfer op is 1-d. This is consistent with the lack of an LLVM instruction to dynamically index into an aggregate (see the Vector dialect lowering to LLVM deep dive).

An instruction such as:

vector.transfer_write %vec, %A[%a, %b, %c] :
  vector<9x17x15xf32>, memref<?x?x?xf32>

Lowers to pseudo-IR resembling (unpacking one dimension):

%0 = alloca() : memref<vector<9x17x15xf32>>
store %vec, %0[] : memref<vector<9x17x15xf32>>
%1 = vector.type_cast %0 :
  memref<vector<9x17x15xf32>> to memref<9xvector<17x15xf32>>
affine.for %I = 0 to 9 {
  %dim = dim %A, 0 : memref<?x?x?xf32>
  %add = affine.apply %I + %a
  %cmp = arith.cmpi "slt", %add, %dim : index
  scf.if %cmp {
    %vec_2d = load %1[%I] : memref<9xvector<17x15xf32>>
    vector.transfer_write %vec_2d, %A[%add, %b, %c] :
      vector<17x15xf32>, memref<?x?x?xf32>

When applying the pattern a second time, the existing alloca() operation is reused and only a second vector.type_cast is added.

Definition at line 52 of file VectorToSCF.h.

Member Function Documentation

enableFullUnroll()

VectorTransferToSCFOptions& mlir::VectorTransferToSCFOptions::enableFullUnroll ( bool  u = true )

inline

Definition at line 68 of file VectorToSCF.h.

References unroll.

enableLowerScalable()

VectorTransferToSCFOptions mlir::VectorTransferToSCFOptions::enableLowerScalable ( bool  enable = true )

inline

Definition at line 76 of file VectorToSCF.h.

References lowerScalable.

enableLowerTensors()

VectorTransferToSCFOptions& mlir::VectorTransferToSCFOptions::enableLowerTensors ( bool  l = true )

inline

Definition at line 62 of file VectorToSCF.h.

References lowerTensors.

setTargetRank()

VectorTransferToSCFOptions& mlir::VectorTransferToSCFOptions::setTargetRank ( unsigned  r )

inline

Definition at line 55 of file VectorToSCF.h.

Member Data Documentation

lowerScalable

bool mlir::VectorTransferToSCFOptions::lowerScalable = false

Enable scalable vector specific lowerings (which introduce loops).

These work alongside fullUnroll (which unrolls until the first scalable dimension).

Definition at line 75 of file VectorToSCF.h.

Referenced by enableLowerScalable().

lowerTensors

bool mlir::VectorTransferToSCFOptions::lowerTensors = false

Allows vector transfers that operated on tensors to be lowered (this is an uncommon alternative).

Definition at line 61 of file VectorToSCF.h.

Referenced by enableLowerTensors().

targetRank

unsigned mlir::VectorTransferToSCFOptions::targetRank = 1

Minimal rank to which vector transfer are lowered.

Definition at line 54 of file VectorToSCF.h.

unroll

bool mlir::VectorTransferToSCFOptions::unroll = false

Triggers full unrolling (vs iterating with a loop) during transfer to scf.

Definition at line 67 of file VectorToSCF.h.

Referenced by enableFullUnroll().

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

• include/mlir/Conversion/VectorToSCF/VectorToSCF.h