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Revert D145226 "[mlir][Transforms][NFC] CSE: Add non-pass entry point"

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This reverts commit 189033e6be.

This commit causes memory leak. See comments on D145226.
This commit is contained in:
Fangrui Song
2023-06-29 12:53:31 -07:00
parent 1221526681
commit 9979417d4d
3 changed files with 33 additions and 134 deletions
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6
mlir/include/mlir/IR/PatternMatch.h
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@@ -627,12 +627,6 @@ public:
/// in-place operation modification is about to happen.
void replaceUsesWithIf(Value from, Value to,
function_ref<bool(OpOperand &)> functor);
void replaceUsesWithIf(ValueRange from, ValueRange to,
function_ref<bool(OpOperand &)> functor) {
assert(from.size() == to.size() && "incorrect number of replacements");
for (auto it : llvm::zip(from, to))
replaceUsesWithIf(std::get<0>(it), std::get<1>(it), functor);
}
/// Find uses of `from` and replace them with `to` except if the user is
/// `exceptedUser`. It also marks every modified uses and notifies the

32
mlir/include/mlir/Transforms/CSE.h
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@@ -1,32 +0,0 @@
//===- CSE.h - Common Subexpression Elimination -----------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file declares methods for eliminating common subexpressions.
//
//===----------------------------------------------------------------------===//
#ifndef MLIR_TRANSFORMS_CSE_H_
#define MLIR_TRANSFORMS_CSE_H_
namespace mlir {
class DominanceInfo;
class Operation;
class RewriterBase;
/// Eliminate common subexpressions within the given operation. This transform
/// looks for and deduplicates equivalent operations.
///
/// `changed` indicates whether the IR was modified or not.
void eliminateCommonSubExpressions(RewriterBase &rewriter,
DominanceInfo &domInfo, Operation *op,
bool *changed = nullptr);
} // namespace mlir
#endif // MLIR_TRANSFORMS_CSE_H_

129
mlir/lib/Transforms/CSE.cpp
View File

@@ -11,13 +11,11 @@
//
//===----------------------------------------------------------------------===//
#include "mlir/Transforms/CSE.h"
#include "mlir/Transforms/Passes.h"
#include "mlir/IR/Dominance.h"
#include "mlir/IR/PatternMatch.h"
#include "mlir/Interfaces/SideEffectInterfaces.h"
#include "mlir/Pass/Pass.h"
#include "mlir/Transforms/Passes.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/ScopedHashTable.h"
@@ -58,18 +56,7 @@ struct SimpleOperationInfo : public llvm::DenseMapInfo<Operation *> {
namespace {
/// Simple common sub-expression elimination.
class CSEDriver {
public:
CSEDriver(RewriterBase &rewriter, DominanceInfo &domInfo)
: rewriter(rewriter), domInfo(domInfo) {}
/// Simplify all operations within the given op.
void simplify(Operation *op, bool *changed = nullptr);
int64_t getNumCSE() const { return numCSE; }
int64_t getNumDCE() const { return numDCE; }
private:
struct CSE : public impl::CSEBase<CSE> {
/// Shared implementation of operation elimination and scoped map definitions.
using AllocatorTy = llvm::RecyclingAllocator<
llvm::BumpPtrAllocator,
@@ -107,6 +94,9 @@ private:
void simplifyBlock(ScopedMapTy &knownValues, Block *bb, bool hasSSADominance);
void simplifyRegion(ScopedMapTy &knownValues, Region &region);
void runOnOperation() override;
private:
void replaceUsesAndDelete(ScopedMapTy &knownValues, Operation *op,
Operation *existing, bool hasSSADominance);
@@ -114,54 +104,29 @@ private:
/// between the two operations.
bool hasOtherSideEffectingOpInBetween(Operation *fromOp, Operation *toOp);
/// A rewriter for modifying the IR.
RewriterBase &rewriter;
/// Operations marked as dead and to be erased.
std::vector<Operation *> opsToErase;
DominanceInfo &domInfo;
DominanceInfo *domInfo = nullptr;
MemEffectsCache memEffectsCache;
// Various statistics.
int64_t numCSE = 0;
int64_t numDCE = 0;
};
} // namespace
void CSEDriver::replaceUsesAndDelete(ScopedMapTy &knownValues, Operation *op,
Operation *existing,
bool hasSSADominance) {
void CSE::replaceUsesAndDelete(ScopedMapTy &knownValues, Operation *op,
Operation *existing, bool hasSSADominance) {
// If we find one then replace all uses of the current operation with the
// existing one and mark it for deletion. We can only replace an operand in
// an operation if it has not been visited yet.
if (hasSSADominance) {
// If the region has SSA dominance, then we are guaranteed to have not
// visited any use of the current operation.
if (auto *rewriteListener =
dyn_cast_if_present<RewriterBase::Listener>(rewriter.getListener()))
rewriteListener->notifyOperationReplaced(op, existing);
// Replace all uses, but do not remote the operation yet. This does not
// notify the listener because the original op is not erased.
rewriter.replaceAllUsesWith(op->getResults(), existing->getResults());
op->replaceAllUsesWith(existing);
opsToErase.push_back(op);
} else {
// When the region does not have SSA dominance, we need to check if we
// have visited a use before replacing any use.
auto wasVisited = [&](OpOperand &operand) {
op->replaceUsesWithIf(existing->getResults(), [&](OpOperand &operand) {
return !knownValues.count(operand.getOwner());
};
if (auto *rewriteListener = dyn_cast_if_present<RewriterBase::Listener>(
rewriter.getListener())) {
for (Value v : op->getResults()) {
if (all_of(v.getUses(), wasVisited)) {
rewriteListener->notifyOperationReplaced(op, existing);
}
}
}
// Replace all uses, but do not remote the operation yet. This does not
// notify the listener because the original op is not erased.
rewriter.replaceUsesWithIf(op->getResults(), existing->getResults(),
wasVisited);
});
// There may be some remaining uses of the operation.
if (op->use_empty())
@@ -177,8 +142,7 @@ void CSEDriver::replaceUsesAndDelete(ScopedMapTy &knownValues, Operation *op,
++numCSE;
}
bool CSEDriver::hasOtherSideEffectingOpInBetween(Operation *fromOp,
Operation *toOp) {
bool CSE::hasOtherSideEffectingOpInBetween(Operation *fromOp, Operation *toOp) {
assert(fromOp->getBlock() == toOp->getBlock());
assert(
isa<MemoryEffectOpInterface>(fromOp) &&
@@ -219,9 +183,8 @@ bool CSEDriver::hasOtherSideEffectingOpInBetween(Operation *fromOp,
}
/// Attempt to eliminate a redundant operation.
LogicalResult CSEDriver::simplifyOperation(ScopedMapTy &knownValues,
Operation *op,
bool hasSSADominance) {
LogicalResult CSE::simplifyOperation(ScopedMapTy &knownValues, Operation *op,
bool hasSSADominance) {
// Don't simplify terminator operations.
if (op->hasTrait<OpTrait::IsTerminator>())
return failure();
@@ -277,8 +240,8 @@ LogicalResult CSEDriver::simplifyOperation(ScopedMapTy &knownValues,
return failure();
}
void CSEDriver::simplifyBlock(ScopedMapTy &knownValues, Block *bb,
bool hasSSADominance) {
void CSE::simplifyBlock(ScopedMapTy &knownValues, Block *bb,
bool hasSSADominance) {
for (auto &op : *bb) {
// Most operations don't have regions, so fast path that case.
if (op.getNumRegions() != 0) {
@@ -304,12 +267,12 @@ void CSEDriver::simplifyBlock(ScopedMapTy &knownValues, Block *bb,
memEffectsCache.clear();
}
void CSEDriver::simplifyRegion(ScopedMapTy &knownValues, Region &region) {
void CSE::simplifyRegion(ScopedMapTy &knownValues, Region &region) {
// If the region is empty there is nothing to do.
if (region.empty())
return;
bool hasSSADominance = domInfo.hasSSADominance(&region);
bool hasSSADominance = domInfo->hasSSADominance(&region);
// If the region only contains one block, then simplify it directly.
if (region.hasOneBlock()) {
@@ -334,7 +297,7 @@ void CSEDriver::simplifyRegion(ScopedMapTy &knownValues, Region &region) {
// Process the nodes of the dom tree for this region.
stack.emplace_back(std::make_unique<CFGStackNode>(
knownValues, domInfo.getRootNode(&region)));
knownValues, domInfo->getRootNode(&region)));
while (!stack.empty()) {
auto &currentNode = stack.back();
@@ -359,55 +322,29 @@ void CSEDriver::simplifyRegion(ScopedMapTy &knownValues, Region &region) {
}
}
void CSEDriver::simplify(Operation *op, bool *changed) {
/// Simplify all regions.
void CSE::runOnOperation() {
/// A scoped hash table of defining operations within a region.
ScopedMapTy knownValues;
for (auto &region : op->getRegions())
domInfo = &getAnalysis<DominanceInfo>();
Operation *rootOp = getOperation();
for (auto &region : rootOp->getRegions())
simplifyRegion(knownValues, region);
// If no operations were erased, then we mark all analyses as preserved.
if (opsToErase.empty())
return markAllAnalysesPreserved();
/// Erase any operations that were marked as dead during simplification.
for (auto *op : opsToErase)
rewriter.eraseOp(op);
if (changed)
*changed = !opsToErase.empty();
/// Invalidate dominance info if the IR was changed.
if (!opsToErase.empty())
domInfo.invalidate();
}
void mlir::eliminateCommonSubExpressions(RewriterBase &rewriter,
DominanceInfo &domInfo, Operation *op,
bool *changed) {
CSEDriver driver(rewriter, domInfo);
driver.simplify(op, changed);
}
namespace {
/// CSE pass.
struct CSE : public impl::CSEBase<CSE> {
void runOnOperation() override;
};
} // namespace
void CSE::runOnOperation() {
// Simplify the IR.
IRRewriter rewriter(&getContext());
CSEDriver driver(rewriter, getAnalysis<DominanceInfo>());
bool changed = false;
driver.simplify(getOperation(), &changed);
// Set statistics.
numCSE = driver.getNumCSE();
numDCE = driver.getNumDCE();
// If there was no change to the IR, we mark all analyses as preserved.
if (!changed)
return markAllAnalysesPreserved();
op->erase();
opsToErase.clear();
// We currently don't remove region operations, so mark dominance as
// preserved.
markAnalysesPreserved<DominanceInfo, PostDominanceInfo>();
domInfo = nullptr;
}
std::unique_ptr<Pass> mlir::createCSEPass() { return std::make_unique<CSE>(); }