llvm-project/llvm/tools/llvm-reduce/deltas/ReduceOperandBundles.cpp

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3.7 KiB
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//===- ReduceOperandBundes.cpp - Specialized Delta Pass -------------------===//
//
// 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 implements a function which calls the Generic Delta pass in order
// to reduce uninteresting operand bundes from calls.
//
//===----------------------------------------------------------------------===//
#include "ReduceOperandBundles.h"
#include "Delta.h"
#include "TestRunner.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Sequence.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/IR/InstVisitor.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <iterator>
#include <vector>
namespace llvm {
class Module;
} // namespace llvm
using namespace llvm;
namespace {
/// Given ChunksToKeep, produce a map of calls and indexes of operand bundles
/// to be preserved for each call.
class OperandBundleRemapper : public InstVisitor<OperandBundleRemapper> {
Oracle &O;
public:
DenseMap<CallBase *, std::vector<unsigned>> CallsToRefine;
explicit OperandBundleRemapper(Oracle &O) : O(O) {}
/// So far only CallBase sub-classes can have operand bundles.
/// Let's see which of the operand bundles of this call are to be kept.
void visitCallBase(CallBase &Call) {
if (!Call.hasOperandBundles())
return; // No bundles to begin with.
// Insert this call into map, we will likely want to rebuild it.
auto &OperandBundlesToKeepIndexes = CallsToRefine[&Call];
OperandBundlesToKeepIndexes.reserve(Call.getNumOperandBundles());
// Enumerate every operand bundle on this call.
for (unsigned BundleIndex : seq(0U, Call.getNumOperandBundles()))
if (O.shouldKeep()) // Should we keep this one?
OperandBundlesToKeepIndexes.emplace_back(BundleIndex);
}
};
struct OperandBundleCounter : public InstVisitor<OperandBundleCounter> {
/// How many features (in this case, operand bundles) did we count, total?
int OperandBundeCount = 0;
/// So far only CallBase sub-classes can have operand bundles.
void visitCallBase(CallBase &Call) {
// Just accumulate the total number of operand bundles.
OperandBundeCount += Call.getNumOperandBundles();
}
};
} // namespace
static void maybeRewriteCallWithDifferentBundles(
CallBase *OrigCall, ArrayRef<unsigned> OperandBundlesToKeepIndexes) {
if (OperandBundlesToKeepIndexes.size() == OrigCall->getNumOperandBundles())
return; // Not modifying operand bundles of this call after all.
std::vector<OperandBundleDef> NewBundles;
NewBundles.reserve(OperandBundlesToKeepIndexes.size());
// Actually copy over the bundles that we want to keep.
transform(OperandBundlesToKeepIndexes, std::back_inserter(NewBundles),
[OrigCall](unsigned Index) {
return OperandBundleDef(OrigCall->getOperandBundleAt(Index));
});
// Finally actually replace the bundles on the call.
CallBase *NewCall = CallBase::Create(OrigCall, NewBundles, OrigCall);
OrigCall->replaceAllUsesWith(NewCall);
OrigCall->eraseFromParent();
}
/// Removes out-of-chunk operand bundles from calls.
static void extractOperandBundesFromModule(Oracle &O, Module &Program) {
OperandBundleRemapper R(O);
R.visit(Program);
for (const auto &I : R.CallsToRefine)
maybeRewriteCallWithDifferentBundles(I.first, I.second);
}
void llvm::reduceOperandBundesDeltaPass(TestRunner &Test) {
outs() << "*** Reducing OperandBundes...\n";
runDeltaPass(Test, extractOperandBundesFromModule);
}