#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"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/DominatorInternals.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/ProfileInfo.h"
#include "llvm/Assembly/Writer.h"
bool MoveExtToFormExtLoad(Instruction *I);
bool OptimizeExtUses(Instruction *I);
bool OptimizeSelectInst(SelectInst *SI);
- bool DupRetToEnableTailCallOpts(ReturnInst *RI);
+ bool DupRetToEnableTailCallOpts(BasicBlock *BB);
bool PlaceDbgValues(Function &F);
- bool ConvertLoadToSwitch(LoadInst *LI);
};
}
/// %tmp2 = tail call i32 @f2()
/// ret i32 %tmp2
/// @endcode
-bool CodeGenPrepare::DupRetToEnableTailCallOpts(ReturnInst *RI) {
+bool CodeGenPrepare::DupRetToEnableTailCallOpts(BasicBlock *BB) {
if (!TLI)
return false;
+ ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator());
+ if (!RI)
+ return false;
+
PHINode *PN = 0;
BitCastInst *BCI = 0;
Value *V = RI->getReturnValue();
return false;
}
- BasicBlock *BB = RI->getParent();
if (PN && PN->getParent() != BB)
return false;
// Conservatively require the attributes of the call to match those of the
// return. Ignore noalias because it doesn't affect the call sequence.
Attributes CalleeRetAttr = CS.getAttributes().getRetAttributes();
- if (Attributes::Builder(CalleeRetAttr ^ CallerRetAttr)
- .removeAttribute(Attributes::NoAlias).hasAttributes())
+ if (AttrBuilder(CalleeRetAttr).
+ removeAttribute(Attributes::NoAlias) !=
+ AttrBuilder(CallerRetAttr).
+ removeAttribute(Attributes::NoAlias))
continue;
// Make sure the call instruction is followed by an unconditional branch to
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)) {
if (CallInst *CI = dyn_cast<CallInst>(I))
return OptimizeCallInst(CI);
- if (ReturnInst *RI = dyn_cast<ReturnInst>(I))
- return DupRetToEnableTailCallOpts(RI);
-
if (SelectInst *SI = dyn_cast<SelectInst>(I))
return OptimizeSelectInst(SI);
while (CurInstIterator != BB.end())
MadeChange |= OptimizeInst(CurInstIterator++);
+ MadeChange |= DupRetToEnableTailCallOpts(&BB);
+
return MadeChange;
}
}
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;
-}
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