[llvm] r229893 - [LoopAccesses] Create the analysis pass
Adam Nemet
anemet at apple.com
Thu Feb 19 11:15:04 PST 2015
Author: anemet
Date: Thu Feb 19 13:15:04 2015
New Revision: 229893
URL: http://llvm.org/viewvc/llvm-project?rev=229893&view=rev
Log:
[LoopAccesses] Create the analysis pass
This is a function pass that runs the analysis on demand. The analysis
can be initiated by querying the loop access info via LAA::getInfo. It
either returns the cached info or runs the analysis.
Symbolic stride information continues to reside outside of this analysis
pass. We may move it inside later but it's not a priority for me right
now. The idea is that Loop Distribution won't support run-time stride
checking at least initially.
This means that when querying the analysis, symbolic stride information
can be provided optionally. Whether stride information is used can
invalidate the cache entry and rerun the analysis. Note that if the
loop does not have any symbolic stride, the entry should be preserved
across Loop Distribution and LV.
Since currently the only user of the pass is LV, I just check that the
symbolic stride information didn't change when using a cached result.
On the LV side, LoopVectorizationLegality requests the info object
corresponding to the loop from the analysis pass. A large chunk of the
diff is due to LAI becoming a pointer from a reference.
A test will be added as part of the -analyze patch.
Also tested that with AVX, we generate identical assembly output for the
testsuite (including the external testsuite) before and after.
This is part of the patchset that converts LoopAccessAnalysis into an
actual analysis pass.
Modified:
llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h
llvm/trunk/include/llvm/InitializePasses.h
llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
llvm/trunk/lib/Transforms/Scalar/Scalar.cpp
llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
Modified: llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h?rev=229893&r1=229892&r2=229893&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h (original)
+++ llvm/trunk/include/llvm/Analysis/LoopAccessAnalysis.h Thu Feb 19 13:15:04 2015
@@ -22,6 +22,7 @@
#include "llvm/Analysis/AliasSetTracker.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/ValueHandle.h"
+#include "llvm/Pass.h"
#include "llvm/Support/raw_ostream.h"
namespace llvm {
@@ -138,12 +139,7 @@ public:
LoopAccessInfo(Loop *L, ScalarEvolution *SE, const DataLayout *DL,
const TargetLibraryInfo *TLI, AliasAnalysis *AA,
- DominatorTree *DT) :
- TheLoop(L), SE(SE), DL(DL), TLI(TLI), AA(AA), DT(DT), NumLoads(0),
- NumStores(0), MaxSafeDepDistBytes(-1U), CanVecMem(false) {}
-
- /// \brief Analyze the loop. Replaces symbolic strides using Strides.
- void analyzeLoop(ValueToValueMap &Strides);
+ DominatorTree *DT, ValueToValueMap &Strides);
/// Return true we can analyze the memory accesses in the loop and there are
/// no memory dependence cycles.
@@ -174,7 +170,15 @@ public:
/// couldn't analyze the loop.
Optional<VectorizationReport> &getReport() { return Report; }
+ /// \brief Used to ensure that if the analysis was run with speculating the
+ /// value of symbolic strides, the client queries it with the same assumption.
+ /// Only used in DEBUG build but we don't want NDEBUG-depedent ABI.
+ unsigned NumSymbolicStrides;
+
private:
+ /// \brief Analyze the loop. Substitute symbolic strides using Strides.
+ void analyzeLoop(ValueToValueMap &Strides);
+
void emitAnalysis(VectorizationReport &Message);
/// We need to check that all of the pointers in this list are disjoint
@@ -212,6 +216,49 @@ const SCEV *replaceSymbolicStrideSCEV(Sc
ValueToValueMap &PtrToStride,
Value *Ptr, Value *OrigPtr = nullptr);
+/// \brief This analysis provides dependence information for the memory accesses
+/// of a loop.
+///
+/// It runs the analysis for a loop on demand. This can be initiated by
+/// querying the loop access info via LAA::getInfo. getInfo return a
+/// LoopAccessInfo object. See this class for the specifics of what information
+/// is provided.
+class LoopAccessAnalysis : public FunctionPass {
+public:
+ static char ID;
+
+ LoopAccessAnalysis() : FunctionPass(ID) {
+ initializeLoopAccessAnalysisPass(*PassRegistry::getPassRegistry());
+ }
+
+ bool runOnFunction(Function &F) override;
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+ /// \brief Query the result of the loop access information for the loop \p L.
+ ///
+ /// If the client speculates (and then issues run-time checks) for the values
+ /// of symbolic strides, \p Strides provides the mapping (see
+ /// replaceSymbolicStrideSCEV). If there is no cached result available run
+ /// the analysis.
+ LoopAccessInfo &getInfo(Loop *L, ValueToValueMap &Strides);
+
+ void releaseMemory() override {
+ // Invalidate the cache when the pass is freed.
+ LoopAccessInfoMap.clear();
+ }
+
+private:
+ /// \brief The cache.
+ DenseMap<Loop *, std::unique_ptr<LoopAccessInfo>> LoopAccessInfoMap;
+
+ // The used analysis passes.
+ ScalarEvolution *SE;
+ const DataLayout *DL;
+ const TargetLibraryInfo *TLI;
+ AliasAnalysis *AA;
+ DominatorTree *DT;
+};
} // End llvm namespace
#endif
Modified: llvm/trunk/include/llvm/InitializePasses.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/InitializePasses.h?rev=229893&r1=229892&r2=229893&view=diff
==============================================================================
--- llvm/trunk/include/llvm/InitializePasses.h (original)
+++ llvm/trunk/include/llvm/InitializePasses.h Thu Feb 19 13:15:04 2015
@@ -281,6 +281,7 @@ void initializeVirtRegRewriterPass(PassR
void initializeInstSimplifierPass(PassRegistry&);
void initializeUnpackMachineBundlesPass(PassRegistry&);
void initializeFinalizeMachineBundlesPass(PassRegistry&);
+void initializeLoopAccessAnalysisPass(PassRegistry&);
void initializeLoopVectorizePass(PassRegistry&);
void initializeSLPVectorizerPass(PassRegistry&);
void initializeBBVectorizePass(PassRegistry&);
Modified: llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp?rev=229893&r1=229892&r2=229893&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp Thu Feb 19 13:15:04 2015
@@ -1230,3 +1230,64 @@ LoopAccessInfo::addRuntimeCheck(Instruct
FirstInst = getFirstInst(FirstInst, Check, Loc);
return std::make_pair(FirstInst, Check);
}
+
+LoopAccessInfo::LoopAccessInfo(Loop *L, ScalarEvolution *SE,
+ const DataLayout *DL,
+ const TargetLibraryInfo *TLI, AliasAnalysis *AA,
+ DominatorTree *DT, ValueToValueMap &Strides)
+ : TheLoop(L), SE(SE), DL(DL), TLI(TLI), AA(AA), DT(DT), NumLoads(0),
+ NumStores(0), MaxSafeDepDistBytes(-1U), CanVecMem(false) {
+ analyzeLoop(Strides);
+}
+
+LoopAccessInfo &LoopAccessAnalysis::getInfo(Loop *L, ValueToValueMap &Strides) {
+ auto &LAI = LoopAccessInfoMap[L];
+
+#ifndef NDEBUG
+ assert((!LAI || LAI->NumSymbolicStrides == Strides.size()) &&
+ "Symbolic strides changed for loop");
+#endif
+
+ if (!LAI) {
+ LAI = llvm::make_unique<LoopAccessInfo>(L, SE, DL, TLI, AA, DT, Strides);
+#ifndef NDEBUG
+ LAI->NumSymbolicStrides = Strides.size();
+#endif
+ }
+ return *LAI.get();
+}
+
+bool LoopAccessAnalysis::runOnFunction(Function &F) {
+ SE = &getAnalysis<ScalarEvolution>();
+ DL = F.getParent()->getDataLayout();
+ auto *TLIP = getAnalysisIfAvailable<TargetLibraryInfoWrapperPass>();
+ TLI = TLIP ? &TLIP->getTLI() : nullptr;
+ AA = &getAnalysis<AliasAnalysis>();
+ DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+
+ return false;
+}
+
+void LoopAccessAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<ScalarEvolution>();
+ AU.addRequired<AliasAnalysis>();
+ AU.addRequired<DominatorTreeWrapperPass>();
+
+ AU.setPreservesAll();
+}
+
+char LoopAccessAnalysis::ID = 0;
+static const char laa_name[] = "Loop Access Analysis";
+#define LAA_NAME "loop-accesses"
+
+INITIALIZE_PASS_BEGIN(LoopAccessAnalysis, LAA_NAME, laa_name, false, true)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_END(LoopAccessAnalysis, LAA_NAME, laa_name, false, true)
+
+namespace llvm {
+ Pass *createLAAPass() {
+ return new LoopAccessAnalysis();
+ }
+}
Modified: llvm/trunk/lib/Transforms/Scalar/Scalar.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Scalar.cpp?rev=229893&r1=229892&r2=229893&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/Scalar.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/Scalar.cpp Thu Feb 19 13:15:04 2015
@@ -46,6 +46,7 @@ void llvm::initializeScalarOpts(PassRegi
initializeJumpThreadingPass(Registry);
initializeLICMPass(Registry);
initializeLoopDeletionPass(Registry);
+ initializeLoopAccessAnalysisPass(Registry);
initializeLoopInstSimplifyPass(Registry);
initializeLoopRotatePass(Registry);
initializeLoopStrengthReducePass(Registry);
Modified: llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp?rev=229893&r1=229892&r2=229893&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp (original)
+++ llvm/trunk/lib/Transforms/Vectorize/LoopVectorize.cpp Thu Feb 19 13:15:04 2015
@@ -531,12 +531,11 @@ public:
LoopVectorizationLegality(Loop *L, ScalarEvolution *SE, const DataLayout *DL,
DominatorTree *DT, TargetLibraryInfo *TLI,
AliasAnalysis *AA, Function *F,
- const TargetTransformInfo *TTI)
+ const TargetTransformInfo *TTI,
+ LoopAccessAnalysis *LAA)
: NumPredStores(0), TheLoop(L), SE(SE), DL(DL),
- TLI(TLI), TheFunction(F), TTI(TTI), DT(DT), Induction(nullptr),
- WidestIndTy(nullptr),
- LAI(L, SE, DL, TLI, AA, DT),
- HasFunNoNaNAttr(false) {}
+ TLI(TLI), TheFunction(F), TTI(TTI), DT(DT), LAA(LAA), LAI(nullptr),
+ Induction(nullptr), WidestIndTy(nullptr), HasFunNoNaNAttr(false) {}
/// This enum represents the kinds of reductions that we support.
enum ReductionKind {
@@ -722,18 +721,18 @@ public:
/// Returns the information that we collected about runtime memory check.
LoopAccessInfo::RuntimePointerCheck *getRuntimePointerCheck() {
- return LAI.getRuntimePointerCheck();
+ return LAI->getRuntimePointerCheck();
}
LoopAccessInfo *getLAI() {
- return &LAI;
+ return LAI;
}
/// This function returns the identity element (or neutral element) for
/// the operation K.
static Constant *getReductionIdentity(ReductionKind K, Type *Tp);
- unsigned getMaxSafeDepDistBytes() { return LAI.getMaxSafeDepDistBytes(); }
+ unsigned getMaxSafeDepDistBytes() { return LAI->getMaxSafeDepDistBytes(); }
bool hasStride(Value *V) { return StrideSet.count(V); }
bool mustCheckStrides() { return !StrideSet.empty(); }
@@ -758,10 +757,10 @@ public:
return (MaskedOp.count(I) != 0);
}
unsigned getNumStores() const {
- return LAI.getNumStores();
+ return LAI->getNumStores();
}
unsigned getNumLoads() const {
- return LAI.getNumLoads();
+ return LAI->getNumLoads();
}
unsigned getNumPredStores() const {
return NumPredStores;
@@ -836,6 +835,11 @@ private:
const TargetTransformInfo *TTI;
/// Dominator Tree.
DominatorTree *DT;
+ // LoopAccess analysis.
+ LoopAccessAnalysis *LAA;
+ // And the loop-accesses info corresponding to this loop. This pointer is
+ // null until canVectorizeMemory sets it up.
+ LoopAccessInfo *LAI;
// --- vectorization state --- //
@@ -857,7 +861,7 @@ private:
/// This set holds the variables which are known to be uniform after
/// vectorization.
SmallPtrSet<Instruction*, 4> Uniforms;
- LoopAccessInfo LAI;
+
/// Can we assume the absence of NaNs.
bool HasFunNoNaNAttr;
@@ -1239,6 +1243,7 @@ struct LoopVectorize : public FunctionPa
TargetLibraryInfo *TLI;
AliasAnalysis *AA;
AssumptionCache *AC;
+ LoopAccessAnalysis *LAA;
bool DisableUnrolling;
bool AlwaysVectorize;
@@ -1256,6 +1261,7 @@ struct LoopVectorize : public FunctionPa
TLI = TLIP ? &TLIP->getTLI() : nullptr;
AA = &getAnalysis<AliasAnalysis>();
AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
+ LAA = &getAnalysis<LoopAccessAnalysis>();
// Compute some weights outside of the loop over the loops. Compute this
// using a BranchProbability to re-use its scaling math.
@@ -1366,7 +1372,7 @@ struct LoopVectorize : public FunctionPa
}
// Check if it is legal to vectorize the loop.
- LoopVectorizationLegality LVL(L, SE, DL, DT, TLI, AA, F, TTI);
+ LoopVectorizationLegality LVL(L, SE, DL, DT, TLI, AA, F, TTI, LAA);
if (!LVL.canVectorize()) {
DEBUG(dbgs() << "LV: Not vectorizing: Cannot prove legality.\n");
emitMissedWarning(F, L, Hints);
@@ -1471,6 +1477,7 @@ struct LoopVectorize : public FunctionPa
AU.addRequired<ScalarEvolution>();
AU.addRequired<TargetTransformInfoWrapperPass>();
AU.addRequired<AliasAnalysis>();
+ AU.addRequired<LoopAccessAnalysis>();
AU.addPreserved<LoopInfoWrapperPass>();
AU.addPreserved<DominatorTreeWrapperPass>();
AU.addPreserved<AliasAnalysis>();
@@ -1642,7 +1649,7 @@ int LoopVectorizationLegality::isConsecu
}
bool LoopVectorizationLegality::isUniform(Value *V) {
- return LAI.isUniform(V);
+ return LAI->isUniform(V);
}
InnerLoopVectorizer::VectorParts&
@@ -3382,7 +3389,7 @@ bool LoopVectorizationLegality::canVecto
collectLoopUniforms();
DEBUG(dbgs() << "LV: We can vectorize this loop" <<
- (LAI.getRuntimePointerCheck()->Need ? " (with a runtime bound check)" :
+ (LAI->getRuntimePointerCheck()->Need ? " (with a runtime bound check)" :
"")
<<"!\n");
@@ -3807,11 +3814,11 @@ void LoopVectorizationLegality::collectL
}
bool LoopVectorizationLegality::canVectorizeMemory() {
- LAI.analyzeLoop(Strides);
- auto &OptionalReport = LAI.getReport();
+ LAI = &LAA->getInfo(TheLoop, Strides);
+ auto &OptionalReport = LAI->getReport();
if (OptionalReport)
emitAnalysis(*OptionalReport);
- return LAI.canVectorizeMemory();
+ return LAI->canVectorizeMemory();
}
static bool hasMultipleUsesOf(Instruction *I,
@@ -4986,6 +4993,7 @@ INITIALIZE_PASS_DEPENDENCY(ScalarEvoluti
INITIALIZE_PASS_DEPENDENCY(LCSSA)
INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
+INITIALIZE_PASS_DEPENDENCY(LoopAccessAnalysis)
INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false)
namespace llvm {
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