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-rw-r--r--lib/Target/TargetTransformImpl.cpp7
-rw-r--r--lib/Transforms/Scalar/CodeGenPrepare.cpp114
-rw-r--r--lib/Transforms/Scalar/SimplifyCFGPass.cpp12
-rw-r--r--lib/Transforms/Utils/SimplifyCFG.cpp21
4 files changed, 31 insertions, 123 deletions
diff --git a/lib/Target/TargetTransformImpl.cpp b/lib/Target/TargetTransformImpl.cpp
index 27877a9..38c704f 100644
--- a/lib/Target/TargetTransformImpl.cpp
+++ b/lib/Target/TargetTransformImpl.cpp
@@ -49,6 +49,12 @@ unsigned ScalarTargetTransformImpl::getJumpBufSize() const {
return TLI->getJumpBufSize();
}
+bool ScalarTargetTransformImpl::shouldBuildLookupTables() const {
+ return TLI->supportJumpTables() &&
+ (TLI->isOperationLegalOrCustom(ISD::BR_JT, MVT::Other) ||
+ TLI->isOperationLegalOrCustom(ISD::BRIND, MVT::Other));
+}
+
//===----------------------------------------------------------------------===//
//
// Calls used by the vectorizers.
@@ -313,4 +319,3 @@ VectorTargetTransformImpl::getNumberOfParts(Type *Tp) const {
getTypeLegalizationCost(Tp->getContext(), TLI->getValueType(Tp));
return LT.first;
}
-
diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index 74e310f..9cd5381 100644
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -18,7 +18,6 @@
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
-#include "llvm/GlobalVariable.h"
#include "llvm/IRBuilder.h"
#include "llvm/InlineAsm.h"
#include "llvm/Instructions.h"
@@ -128,7 +127,6 @@ namespace {
bool OptimizeSelectInst(SelectInst *SI);
bool DupRetToEnableTailCallOpts(ReturnInst *RI);
bool PlaceDbgValues(Function &F);
- bool ConvertLoadToSwitch(LoadInst *LI);
};
}
@@ -1292,11 +1290,9 @@ bool CodeGenPrepare::OptimizeInst(Instruction *I) {
return OptimizeCmpExpression(CI);
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
- bool Changed = false;
if (TLI)
- Changed |= OptimizeMemoryInst(I, I->getOperand(0), LI->getType());
- Changed |= ConvertLoadToSwitch(LI);
- return Changed;
+ return OptimizeMemoryInst(I, I->getOperand(0), LI->getType());
+ return false;
}
if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
@@ -1376,109 +1372,3 @@ bool CodeGenPrepare::PlaceDbgValues(Function &F) {
}
return MadeChange;
}
-
-static bool TargetSupportsJumpTables(const TargetLowering &TLI) {
- return TLI.supportJumpTables() &&
- (TLI.isOperationLegalOrCustom(ISD::BR_JT, MVT::Other) ||
- TLI.isOperationLegalOrCustom(ISD::BRIND, MVT::Other));
-}
-
-/// ConvertLoadToSwitch - Convert loads from constant lookup tables into
-/// switches. This undos the switch-to-lookup table transformation in
-/// SimplifyCFG for targets where that is inprofitable.
-bool CodeGenPrepare::ConvertLoadToSwitch(LoadInst *LI) {
- // This only applies to targets that don't support jump tables.
- if (!TLI || TargetSupportsJumpTables(*TLI))
- return false;
-
- // FIXME: In the future, it would be desirable to have enough target
- // information in SimplifyCFG, so we could decide at that stage whether to
- // transform the switch to a lookup table or not, and this
- // reverse-transformation could be removed.
-
- GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(LI->getPointerOperand());
- if (!GEP || !GEP->isInBounds() || GEP->getPointerAddressSpace())
- return false;
- if (GEP->getNumIndices() != 2)
- return false;
- Value *FirstIndex = GEP->idx_begin()[0];
- ConstantInt *FirstIndexInt = dyn_cast<ConstantInt>(FirstIndex);
- if (!FirstIndexInt || !FirstIndexInt->isZero())
- return false;
-
- Value *TableIndex = GEP->idx_begin()[1];
- IntegerType *TableIndexTy = cast<IntegerType>(TableIndex->getType());
-
- GlobalVariable *GV = dyn_cast<GlobalVariable>(GEP->getPointerOperand());
- if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer())
- return false;
-
- Constant *Arr = GV->getInitializer();
- uint64_t NumElements;
- if (ConstantArray *CA = dyn_cast<ConstantArray>(Arr))
- NumElements = CA->getType()->getNumElements();
- else if (ConstantDataArray *CDA = dyn_cast<ConstantDataArray>(Arr))
- NumElements = CDA->getNumElements();
- else
- return false;
- if (NumElements < 2)
- return false;
-
- // Split the block.
- BasicBlock *OriginalBB = LI->getParent();
- BasicBlock *PostSwitchBB = OriginalBB->splitBasicBlock(LI);
-
- // Replace OriginalBB's terminator with a switch.
- IRBuilder<> Builder(OriginalBB->getTerminator());
- SwitchInst *Switch = Builder.CreateSwitch(TableIndex, PostSwitchBB,
- NumElements - 1);
- OriginalBB->getTerminator()->eraseFromParent();
-
- // Count the frequency of each value to decide which to use as default.
- SmallDenseMap<Constant*, uint64_t> ValueFreq;
- for (uint64_t I = 0; I < NumElements; ++I)
- ++ValueFreq[Arr->getAggregateElement(I)];
- uint64_t MaxCount = 0;
- Constant *DefaultValue = NULL;
- for (SmallDenseMap<Constant*, uint64_t>::iterator I = ValueFreq.begin(),
- E = ValueFreq.end(); I != E; ++I) {
- if (I->second > MaxCount) {
- MaxCount = I->second;
- DefaultValue = I->first;
- }
- }
- assert(DefaultValue && "No values in the array?");
-
- // Create the phi node in PostSwitchBB, which will replace the load.
- Builder.SetInsertPoint(PostSwitchBB->begin());
- PHINode *PHI = Builder.CreatePHI(LI->getType(), NumElements);
- PHI->addIncoming(DefaultValue, OriginalBB);
-
- // Build basic blocks to target with the switch.
- for (uint64_t I = 0; I < NumElements; ++I) {
- Constant *C = Arr->getAggregateElement(I);
- if (C == DefaultValue) continue; // Already covered by the default case.
-
- BasicBlock *BB = BasicBlock::Create(PostSwitchBB->getContext(),
- "lookup.bb",
- PostSwitchBB->getParent(),
- PostSwitchBB);
- Switch->addCase(ConstantInt::get(TableIndexTy, I), BB);
- Builder.SetInsertPoint(BB);
- Builder.CreateBr(PostSwitchBB);
- PHI->addIncoming(C, BB);
- }
-
- // Remove the load.
- LI->replaceAllUsesWith(PHI);
- LI->eraseFromParent();
-
- // Clean up.
- if (GEP->use_empty())
- GEP->eraseFromParent();
- if (GV->hasUnnamedAddr() && GV->hasPrivateLinkage() && GV->use_empty())
- GV->eraseFromParent();
-
- CurInstIterator = Switch;
- return true;
-}
diff --git a/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index 84b820b..9f24bb6 100644
--- a/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -35,6 +35,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/TargetTransformInfo.h"
using namespace llvm;
STATISTIC(NumSimpl, "Number of blocks simplified");
@@ -293,7 +294,8 @@ static bool mergeEmptyReturnBlocks(Function &F) {
/// iterativelySimplifyCFG - Call SimplifyCFG on all the blocks in the function,
/// iterating until no more changes are made.
-static bool iterativelySimplifyCFG(Function &F, const DataLayout *TD) {
+static bool iterativelySimplifyCFG(Function &F, const DataLayout *TD,
+ const TargetTransformInfo *TTI) {
bool Changed = false;
bool LocalChange = true;
while (LocalChange) {
@@ -302,7 +304,7 @@ static bool iterativelySimplifyCFG(Function &F, const DataLayout *TD) {
// Loop over all of the basic blocks and remove them if they are unneeded...
//
for (Function::iterator BBIt = F.begin(); BBIt != F.end(); ) {
- if (SimplifyCFG(BBIt++, TD)) {
+ if (SimplifyCFG(BBIt++, TD, TTI)) {
LocalChange = true;
++NumSimpl;
}
@@ -317,9 +319,11 @@ static bool iterativelySimplifyCFG(Function &F, const DataLayout *TD) {
//
bool CFGSimplifyPass::runOnFunction(Function &F) {
const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
+ const TargetTransformInfo *TTI =
+ getAnalysisIfAvailable<TargetTransformInfo>();
bool EverChanged = removeUnreachableBlocksFromFn(F);
EverChanged |= mergeEmptyReturnBlocks(F);
- EverChanged |= iterativelySimplifyCFG(F, TD);
+ EverChanged |= iterativelySimplifyCFG(F, TD, TTI);
// If neither pass changed anything, we're done.
if (!EverChanged) return false;
@@ -333,7 +337,7 @@ bool CFGSimplifyPass::runOnFunction(Function &F) {
return true;
do {
- EverChanged = iterativelySimplifyCFG(F, TD);
+ EverChanged = iterativelySimplifyCFG(F, TD, TTI);
EverChanged |= removeUnreachableBlocksFromFn(F);
} while (EverChanged);
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index f05a8ba..04ffc90 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -14,6 +14,7 @@
#define DEBUG_TYPE "simplifycfg"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Constants.h"
+#include "llvm/DataLayout.h"
#include "llvm/DerivedTypes.h"
#include "llvm/GlobalVariable.h"
#include "llvm/IRBuilder.h"
@@ -39,7 +40,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/NoFolder.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/DataLayout.h"
+#include "llvm/TargetTransformInfo.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include <algorithm>
#include <set>
@@ -82,6 +83,7 @@ namespace {
class SimplifyCFGOpt {
const DataLayout *const TD;
+ const TargetTransformInfo *const TTI;
Value *isValueEqualityComparison(TerminatorInst *TI);
BasicBlock *GetValueEqualityComparisonCases(TerminatorInst *TI,
@@ -101,7 +103,8 @@ class SimplifyCFGOpt {
bool SimplifyCondBranch(BranchInst *BI, IRBuilder <>&Builder);
public:
- explicit SimplifyCFGOpt(const DataLayout *td) : TD(td) {}
+ SimplifyCFGOpt(const DataLayout *td, const TargetTransformInfo *tti)
+ : TD(td), TTI(tti) {}
bool run(BasicBlock *BB);
};
}
@@ -3459,8 +3462,13 @@ static bool ShouldBuildLookupTable(SwitchInst *SI,
/// replace the switch with lookup tables.
static bool SwitchToLookupTable(SwitchInst *SI,
IRBuilder<> &Builder,
- const DataLayout* TD) {
+ const DataLayout* TD,
+ const TargetTransformInfo *TTI) {
assert(SI->getNumCases() > 1 && "Degenerate switch?");
+
+ if (TTI && !TTI->getScalarTargetTransformInfo()->shouldBuildLookupTables())
+ return false;
+
// FIXME: Handle unreachable cases.
// FIXME: If the switch is too sparse for a lookup table, perhaps we could
@@ -3619,7 +3627,7 @@ bool SimplifyCFGOpt::SimplifySwitch(SwitchInst *SI, IRBuilder<> &Builder) {
if (ForwardSwitchConditionToPHI(SI))
return SimplifyCFG(BB) | true;
- if (SwitchToLookupTable(SI, Builder, TD))
+ if (SwitchToLookupTable(SI, Builder, TD, TTI))
return SimplifyCFG(BB) | true;
return false;
@@ -3916,6 +3924,7 @@ bool SimplifyCFGOpt::run(BasicBlock *BB) {
/// eliminates unreachable basic blocks, and does other "peephole" optimization
/// of the CFG. It returns true if a modification was made.
///
-bool llvm::SimplifyCFG(BasicBlock *BB, const DataLayout *TD) {
- return SimplifyCFGOpt(TD).run(BB);
+bool llvm::SimplifyCFG(BasicBlock *BB, const DataLayout *TD,
+ const TargetTransformInfo *TTI) {
+ return SimplifyCFGOpt(TD, TTI).run(BB);
}
generated by cgit v1.1 at 2025-01-19 16:02:10 +0000