RegionUtils.cpp File Reference

#include "mlir/Transforms/RegionUtils.h"
#include "mlir/Analysis/TopologicalSortUtils.h"
#include "mlir/IR/Block.h"
#include "mlir/IR/BuiltinOps.h"
#include "mlir/IR/IRMapping.h"
#include "mlir/IR/Operation.h"
#include "mlir/IR/PatternMatch.h"
#include "mlir/IR/RegionGraphTraits.h"
#include "mlir/IR/Value.h"
#include "mlir/Interfaces/ControlFlowInterfaces.h"
#include "mlir/Interfaces/SideEffectInterfaces.h"
#include "mlir/Support/LogicalResult.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include <deque>
#include <iterator>

Go to the source code of this file.

Functions
static bool	isUseSpeciallyKnownDead (OpOperand &use, LiveMap &liveMap)
static void	processValue (Value value, LiveMap &liveMap)
static void	propagateLiveness (Region &region, LiveMap &liveMap)
static void	propagateTerminatorLiveness (Operation *op, LiveMap &liveMap)
static void	propagateLiveness (Operation *op, LiveMap &liveMap)
static void	eraseTerminatorSuccessorOperands (Operation *terminator, LiveMap &liveMap)
static LogicalResult	deleteDeadness (RewriterBase &rewriter, MutableArrayRef< Region > regions, LiveMap &liveMap)
static bool	ableToUpdatePredOperands (Block *block)
	Returns true if the predecessor terminators of the given block can not have their operands updated. More...
static SmallVector< SmallVector< Value, 8 >, 2 >	pruneRedundantArguments (const SmallVector< SmallVector< Value, 8 >, 2 > &newArguments, RewriterBase &rewriter, unsigned numOldArguments, Block *block)
	Prunes the redundant list of new arguments. More...
static LogicalResult	mergeIdenticalBlocks (RewriterBase &rewriter, Region &region)
	Identify identical blocks within the given region and merge them, inserting new block arguments as necessary. More...
static LogicalResult	mergeIdenticalBlocks (RewriterBase &rewriter, MutableArrayRef< Region > regions)
	Identify identical blocks within the given regions and merge them, inserting new block arguments as necessary. More...
static LogicalResult	dropRedundantArguments (RewriterBase &rewriter, Block &block)
	If a block's argument is always the same across different invocations, then drop the argument and use the value directly inside the block. More...
static LogicalResult	dropRedundantArguments (RewriterBase &rewriter, MutableArrayRef< Region > regions)
	This optimization drops redundant argument to blocks. More...

Function Documentation

ableToUpdatePredOperands()

static bool ableToUpdatePredOperands ( Block *  block )

static

Returns true if the predecessor terminators of the given block can not have their operands updated.

Definition at line 674 of file RegionUtils.cpp.

References mlir::Block::pred_begin(), and mlir::Block::pred_end().

deleteDeadness()

static LogicalResult deleteDeadness ( RewriterBase &  rewriter, MutableArrayRef< Region >  regions, LiveMap &  liveMap  )

static

Definition at line 413 of file RegionUtils.cpp.

References mlir::Region::empty(), mlir::RewriterBase::eraseOp(), eraseTerminatorSuccessorOperands(), mlir::Region::front(), and mlir::Region::getBlocks().

Referenced by mlir::runRegionDCE().

dropRedundantArguments() [1/2]

static LogicalResult dropRedundantArguments ( RewriterBase &  rewriter, Block &  block  )

static

If a block's argument is always the same across different invocations, then drop the argument and use the value directly inside the block.

Definition at line 930 of file RegionUtils.cpp.

References mlir::detail::enumerate(), mlir::SuccessorOperands::erase(), mlir::Block::eraseArgument(), mlir::Block::getArguments(), mlir::SuccessorOperands::getForwardedOperands(), mlir::Block::pred_begin(), mlir::Block::pred_end(), and mlir::RewriterBase::replaceAllUsesWith().

Referenced by dropRedundantArguments(), and mlir::simplifyRegions().

dropRedundantArguments() [2/2]

static LogicalResult dropRedundantArguments ( RewriterBase &  rewriter, MutableArrayRef< Region >  regions  )

static

This optimization drops redundant argument to blocks.

I.e., if a given argument to a block receives the same value from each of the block predecessors, we can remove the argument from the block and use directly the original value. This is a simple example:

cond = llvm.call @rand() : () -> i1 val0 = llvm.mlir.constant(1 : i64) : i64 val1 = llvm.mlir.constant(2 : i64) : i64 val2 = llvm.mlir.constant(3 : i64) : i64 llvm.cond_br cond, ^bb1(val0 : i64, val1 : i64), ^bb2(val0 : i64, val2 : i64)

^bb1(arg0 : i64, arg1 : i64): llvm.call @foo(arg0, arg1)

The previous IR can be rewritten as: cond = llvm.call @rand() : () -> i1 val0 = llvm.mlir.constant(1 : i64) : i64 val1 = llvm.mlir.constant(2 : i64) : i64 val2 = llvm.mlir.constant(3 : i64) : i64 llvm.cond_br cond, ^bb1(val1 : i64), ^bb2(val2 : i64)

^bb1(arg0 : i64): llvm.call @foo(val0, arg0)

Definition at line 1012 of file RegionUtils.cpp.

References dropRedundantArguments().

eraseTerminatorSuccessorOperands()

static void eraseTerminatorSuccessorOperands ( Operation *  terminator, LiveMap &  liveMap  )

static

Definition at line 387 of file RegionUtils.cpp.

References mlir::SuccessorOperands::erase(), mlir::Block::getArgument(), mlir::Operation::getNumSuccessors(), mlir::Operation::getSuccessor(), and mlir::SuccessorOperands::size().

Referenced by deleteDeadness().

isUseSpeciallyKnownDead()

static bool isUseSpeciallyKnownDead ( OpOperand &  use, LiveMap &  liveMap  )

static

Definition at line 282 of file RegionUtils.cpp.

References mlir::OpOperand::getOperandNumber(), mlir::detail::IROperandBase::getOwner(), and mlir::Operation::hasTrait().

mergeIdenticalBlocks() [1/2]

static LogicalResult mergeIdenticalBlocks ( RewriterBase &  rewriter, MutableArrayRef< Region >  regions  )

static

Identify identical blocks within the given regions and merge them, inserting new block arguments as necessary.

Definition at line 905 of file RegionUtils.cpp.

References mergeIdenticalBlocks().

mergeIdenticalBlocks() [2/2]

static LogicalResult mergeIdenticalBlocks ( RewriterBase &  rewriter, Region &  region  )

static

Identify identical blocks within the given region and merge them, inserting new block arguments as necessary.

Returns success if any blocks were merged, failure otherwise.

Definition at line 849 of file RegionUtils.cpp.

References mlir::Region::empty(), mlir::Block::getArguments(), mlir::Operation::getRegions(), and mlir::Block::getSuccessors().

Referenced by mergeIdenticalBlocks(), and mlir::simplifyRegions().

processValue()

static void processValue ( Value  value, LiveMap &  liveMap  )

static

Definition at line 305 of file RegionUtils.cpp.

References mlir::Value::getUses().

Referenced by getBackwardSliceImpl(), and propagateLiveness().

propagateLiveness() [1/2]

static void propagateLiveness ( Operation *  op, LiveMap &  liveMap  )

static

Definition at line 341 of file RegionUtils.cpp.

References mlir::Operation::getRegions(), mlir::Operation::getResults(), mlir::Operation::hasTrait(), processValue(), propagateLiveness(), propagateTerminatorLiveness(), and mlir::wouldOpBeTriviallyDead().

propagateLiveness() [2/2]

static void propagateLiveness ( Region &  region, LiveMap &  liveMap  )

static

Definition at line 363 of file RegionUtils.cpp.

References mlir::Region::empty(), mlir::Region::front(), and processValue().

Referenced by propagateLiveness(), and mlir::runRegionDCE().

propagateTerminatorLiveness()

static void propagateTerminatorLiveness ( Operation *  op, LiveMap &  liveMap  )

static

Definition at line 317 of file RegionUtils.cpp.

References mlir::Block::getArgument(), mlir::Operation::getNumSuccessors(), mlir::SuccessorOperands::getProducedOperandCount(), mlir::Operation::getSuccessor(), and mlir::Operation::getSuccessors().

Referenced by propagateLiveness().

pruneRedundantArguments()

static SmallVector<SmallVector<Value, 8>, 2> pruneRedundantArguments ( const SmallVector< SmallVector< Value, 8 >, 2 > &  newArguments, RewriterBase &  rewriter, unsigned  numOldArguments, Block *  block  )

static

Prunes the redundant list of new arguments.

E.g., if we are passing an argument list like [x, y, z, x] this would return [x, y, z] and it would update the block (to whom the argument are passed to) accordingly. The new arguments are passed as arguments at the back of the block, hence we need to know how many numOldArguments were before, in order to correctly replace the new arguments in the block

Definition at line 688 of file RegionUtils.cpp.

References mlir::detail::enumerate(), mlir::Block::eraseArgument(), mlir::Block::getArgument(), mlir::Block::getArguments(), and mlir::RewriterBase::replaceAllUsesWith().