b0aa36f9c2
The existing LoopRotation.cpp is implemented as one of loop passes instead of being a utility. The user cannot easily perform the loop rotation selectively (or on demand) under different optimization level. For example, the loop rotation is needed as part of the logic to convert a loop into a loop with bottom test for a transformation. If the loop rotation is simply added as a loop pass before the transformation, the pass is skipped if it is compiled at –O0 or if it is explicitly disabled by the user, causing the compiler to generate incorrect code. Furthermore, as a loop pass it will rotate all loops instead of just the relevant loops. We provide a utility interface for the loop rotation so that the loop rotation can be called on demand. The changeset is as follows: - Create a new file lib/Transforms/Utils/LoopRotationUtils.cpp and move the main implementation of class LoopRotate into this file. - Create a new file llvm/include/Transform/Utils/LoopRotationUtils.h with the interface LoopRotation(...). - Original LoopRotation.cpp is changed to use the utility function LoopRotation in LoopRotationUtils.cpp. This is done in the same way community did for mem-to-reg implementation. Patch by Jin Lin! Differential Revision: https://reviews.llvm.org/D44595 llvm-svn: 328766
104 lines
3.8 KiB
C++
104 lines
3.8 KiB
C++
//===- LoopRotation.cpp - Loop Rotation Pass ------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements Loop Rotation Pass.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Transforms/Scalar/LoopRotation.h"
|
|
#include "llvm/ADT/Statistic.h"
|
|
#include "llvm/Analysis/InstructionSimplify.h"
|
|
#include "llvm/Analysis/LoopPass.h"
|
|
#include "llvm/Analysis/ScalarEvolution.h"
|
|
#include "llvm/Analysis/TargetTransformInfo.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Transforms/Scalar.h"
|
|
#include "llvm/Transforms/Scalar/LoopPassManager.h"
|
|
#include "llvm/Transforms/Utils/LoopRotationUtils.h"
|
|
#include "llvm/Transforms/Utils/LoopUtils.h"
|
|
using namespace llvm;
|
|
|
|
#define DEBUG_TYPE "loop-rotate"
|
|
|
|
static cl::opt<unsigned> DefaultRotationThreshold(
|
|
"rotation-max-header-size", cl::init(16), cl::Hidden,
|
|
cl::desc("The default maximum header size for automatic loop rotation"));
|
|
|
|
LoopRotatePass::LoopRotatePass(bool EnableHeaderDuplication)
|
|
: EnableHeaderDuplication(EnableHeaderDuplication) {}
|
|
|
|
PreservedAnalyses LoopRotatePass::run(Loop &L, LoopAnalysisManager &AM,
|
|
LoopStandardAnalysisResults &AR,
|
|
LPMUpdater &) {
|
|
int Threshold = EnableHeaderDuplication ? DefaultRotationThreshold : 0;
|
|
const DataLayout &DL = L.getHeader()->getModule()->getDataLayout();
|
|
const SimplifyQuery SQ = getBestSimplifyQuery(AR, DL);
|
|
|
|
bool Changed =
|
|
LoopRotation(&L, Threshold, &AR.LI, &AR.TTI, &AR.AC, &AR.DT, &AR.SE, SQ);
|
|
|
|
if (!Changed)
|
|
return PreservedAnalyses::all();
|
|
|
|
return getLoopPassPreservedAnalyses();
|
|
}
|
|
|
|
namespace {
|
|
|
|
class LoopRotateLegacyPass : public LoopPass {
|
|
unsigned MaxHeaderSize;
|
|
|
|
public:
|
|
static char ID; // Pass ID, replacement for typeid
|
|
LoopRotateLegacyPass(int SpecifiedMaxHeaderSize = -1) : LoopPass(ID) {
|
|
initializeLoopRotateLegacyPassPass(*PassRegistry::getPassRegistry());
|
|
if (SpecifiedMaxHeaderSize == -1)
|
|
MaxHeaderSize = DefaultRotationThreshold;
|
|
else
|
|
MaxHeaderSize = unsigned(SpecifiedMaxHeaderSize);
|
|
}
|
|
|
|
// LCSSA form makes instruction renaming easier.
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override {
|
|
AU.addRequired<AssumptionCacheTracker>();
|
|
AU.addRequired<TargetTransformInfoWrapperPass>();
|
|
getLoopAnalysisUsage(AU);
|
|
}
|
|
|
|
bool runOnLoop(Loop *L, LPPassManager &LPM) override {
|
|
if (skipLoop(L))
|
|
return false;
|
|
Function &F = *L->getHeader()->getParent();
|
|
|
|
auto *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
|
|
const auto *TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
|
|
auto *AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
|
|
auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
|
|
auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
|
|
auto *SEWP = getAnalysisIfAvailable<ScalarEvolutionWrapperPass>();
|
|
auto *SE = SEWP ? &SEWP->getSE() : nullptr;
|
|
const SimplifyQuery SQ = getBestSimplifyQuery(*this, F);
|
|
return LoopRotation(L, MaxHeaderSize, LI, TTI, AC, DT, SE, SQ);
|
|
}
|
|
};
|
|
}
|
|
|
|
char LoopRotateLegacyPass::ID = 0;
|
|
INITIALIZE_PASS_BEGIN(LoopRotateLegacyPass, "loop-rotate", "Rotate Loops",
|
|
false, false)
|
|
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
|
|
INITIALIZE_PASS_DEPENDENCY(LoopPass)
|
|
INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
|
|
INITIALIZE_PASS_END(LoopRotateLegacyPass, "loop-rotate", "Rotate Loops", false,
|
|
false)
|
|
|
|
Pass *llvm::createLoopRotatePass(int MaxHeaderSize) {
|
|
return new LoopRotateLegacyPass(MaxHeaderSize);
|
|
}
|