#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
-#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/CFG.h"
+#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/InlineCost.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Function.h"
char TailCallElim::ID = 0;
INITIALIZE_PASS_BEGIN(TailCallElim, "tailcallelim",
"Tail Call Elimination", false, false)
-INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
+INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
INITIALIZE_PASS_END(TailCallElim, "tailcallelim",
"Tail Call Elimination", false, false)
}
void TailCallElim::getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addRequired<TargetTransformInfo>();
+ AU.addRequired<TargetTransformInfoWrapperPass>();
}
/// \brief Scan the specified function for alloca instructions.
auto AddUsesToWorklist = [&](Value *V) {
for (auto &U : V->uses()) {
- if (!Visited.insert(&U))
+ if (!Visited.insert(&U).second)
continue;
Worklist.push_back(&U);
}
}
void callUsesLocalStack(CallSite CS, bool IsNocapture) {
- // Add it to the list of alloca users. If it's already there, skip further
- // processing.
- if (!AllocaUsers.insert(CS.getInstruction()))
- return;
+ // Add it to the list of alloca users.
+ AllocaUsers.insert(CS.getInstruction());
- // If it's nocapture then it can't capture the alloca.
+ // If it's nocapture then it can't capture this alloca.
if (IsNocapture)
return;
}
}
- for (auto *SuccBB : successors(BB)) {
+ for (auto *SuccBB : make_range(succ_begin(BB), succ_end(BB))) {
auto &State = Visited[SuccBB];
if (State < Escaped) {
State = Escaped;
// right, so don't even try to convert it...
if (F.getFunctionType()->isVarArg()) return false;
- TTI = &getAnalysis<TargetTransformInfo>();
+ TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
BasicBlock *OldEntry = nullptr;
bool TailCallsAreMarkedTail = false;
SmallVector<PHINode*, 8> ArgumentPHIs;
bool MadeChange = false;
- // CanTRETailMarkedCall - If false, we cannot perform TRE on tail calls
- // marked with the 'tail' attribute, because doing so would cause the stack
- // size to increase (real TRE would deallocate variable sized allocas, TRE
- // doesn't).
+ // If false, we cannot perform TRE on tail calls marked with the 'tail'
+ // attribute, because doing so would cause the stack size to increase (real
+ // TRE would deallocate variable sized allocas, TRE doesn't).
bool CanTRETailMarkedCall = CanTRE(F);
// Change any tail recursive calls to loops.
// alloca' is changed from being a static alloca to being a dynamic alloca.
// Until this is resolved, disable this transformation if that would ever
// happen. This bug is PR962.
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+ for (Function::iterator BBI = F.begin(), E = F.end(); BBI != E; /*in loop*/) {
+ BasicBlock *BB = BBI++; // FoldReturnAndProcessPred may delete BB.
if (ReturnInst *Ret = dyn_cast<ReturnInst>(BB->getTerminator())) {
bool Change = ProcessReturningBlock(Ret, OldEntry, TailCallsAreMarkedTail,
ArgumentPHIs, !CanTRETailMarkedCall);
PHINode *PN = ArgumentPHIs[i];
// If the PHI Node is a dynamic constant, replace it with the value it is.
- if (Value *PNV = SimplifyInstruction(PN)) {
+ if (Value *PNV = SimplifyInstruction(PN, F.getParent()->getDataLayout())) {
PN->replaceAllUsesWith(PNV);
PN->eraseFromParent();
}
}
-/// CanMoveAboveCall - Return true if it is safe to move the specified
+/// Return true if it is safe to move the specified
/// instruction from after the call to before the call, assuming that all
/// instructions between the call and this instruction are movable.
///
return true;
}
-// isDynamicConstant - Return true if the specified value is the same when the
-// return would exit as it was when the initial iteration of the recursive
-// function was executed.
-//
-// We currently handle static constants and arguments that are not modified as
-// part of the recursion.
-//
+/// Return true if the specified value is the same when the return would exit
+/// as it was when the initial iteration of the recursive function was executed.
+///
+/// We currently handle static constants and arguments that are not modified as
+/// part of the recursion.
static bool isDynamicConstant(Value *V, CallInst *CI, ReturnInst *RI) {
if (isa<Constant>(V)) return true; // Static constants are always dyn consts
return false;
}
-// getCommonReturnValue - Check to see if the function containing the specified
-// tail call consistently returns the same runtime-constant value at all exit
-// points except for IgnoreRI. If so, return the returned value.
-//
+/// Check to see if the function containing the specified tail call consistently
+/// returns the same runtime-constant value at all exit points except for
+/// IgnoreRI. If so, return the returned value.
static Value *getCommonReturnValue(ReturnInst *IgnoreRI, CallInst *CI) {
Function *F = CI->getParent()->getParent();
Value *ReturnedValue = nullptr;
return ReturnedValue;
}
-/// CanTransformAccumulatorRecursion - If the specified instruction can be
-/// transformed using accumulator recursion elimination, return the constant
-/// which is the start of the accumulator value. Otherwise return null.
-///
+/// If the specified instruction can be transformed using accumulator recursion
+/// elimination, return the constant which is the start of the accumulator
+/// value. Otherwise return null.
Value *TailCallElim::CanTransformAccumulatorRecursion(Instruction *I,
CallInst *CI) {
if (!I->isAssociative() || !I->isCommutative()) return nullptr;
// predecessors and perform TRC there. Look for predecessors that end
// in unconditional branch and recursive call(s).
SmallVector<BranchInst*, 8> UncondBranchPreds;
- for (BasicBlock *Pred : predecessors(BB)) {
+ for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
+ BasicBlock *Pred = *PI;
TerminatorInst *PTI = Pred->getTerminator();
if (BranchInst *BI = dyn_cast<BranchInst>(PTI))
if (BI->isUnconditional())
if (CallInst *CI = FindTRECandidate(BI, CannotTailCallElimCallsMarkedTail)){
DEBUG(dbgs() << "FOLDING: " << *BB
<< "INTO UNCOND BRANCH PRED: " << *Pred);
- EliminateRecursiveTailCall(CI, FoldReturnIntoUncondBranch(Ret, BB, Pred),
- OldEntry, TailCallsAreMarkedTail, ArgumentPHIs,
+ ReturnInst *RI = FoldReturnIntoUncondBranch(Ret, BB, Pred);
+
+ // Cleanup: if all predecessors of BB have been eliminated by
+ // FoldReturnIntoUncondBranch, delete it. It is important to empty it,
+ // because the ret instruction in there is still using a value which
+ // EliminateRecursiveTailCall will attempt to remove.
+ if (!BB->hasAddressTaken() && pred_begin(BB) == pred_end(BB))
+ BB->eraseFromParent();
+
+ EliminateRecursiveTailCall(CI, RI, OldEntry, TailCallsAreMarkedTail,
+ ArgumentPHIs,
CannotTailCallElimCallsMarkedTail);
++NumRetDuped;
Change = true;
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