virtual unsigned getGEPCost(const Value *Ptr,
ArrayRef<const Value *> Operands) const;
+ /// \brief Estimate the cost of a function call when lowered.
+ ///
+ /// The contract for this is the same as \c getOperationCost except that it
+ /// supports an interface that provides extra information specific to call
+ /// instructions.
+ ///
+ /// This is the most basic query for estimating call cost: it only knows the
+ /// function type and (potentially) the number of arguments at the call site.
+ /// The latter is only interesting for varargs function types.
+ virtual unsigned getCallCost(FunctionType *FTy, int NumArgs = -1) const;
+
+ /// \brief Estimate the cost of calling a specific function when lowered.
+ ///
+ /// This overload adds the ability to reason about the particular function
+ /// being called in the event it is a library call with special lowering.
+ virtual unsigned getCallCost(const Function *F, int NumArgs = -1) const;
+
+ /// \brief Estimate the cost of calling a specific function when lowered.
+ ///
+ /// This overload allows specifying a set of candidate argument values.
+ virtual unsigned getCallCost(const Function *F,
+ ArrayRef<const Value *> Arguments) const;
+
+ /// \brief Estimate the cost of an intrinsic when lowered.
+ ///
+ /// Mirrors the \c getCallCost method but uses an intrinsic identifier.
+ virtual unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy,
+ ArrayRef<Type *> ParamTys) const;
+
+ /// \brief Estimate the cost of an intrinsic when lowered.
+ ///
+ /// Mirrors the \c getCallCost method but uses an intrinsic identifier.
+ virtual unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy,
+ ArrayRef<const Value *> Arguments) const;
+
/// \brief Estimate the cost of a given IR user when lowered.
///
/// This can estimate the cost of either a ConstantExpr or Instruction when
/// comments for a detailed explanation of the cost values.
virtual unsigned getUserCost(const User *U) const;
+ /// \brief Test whether calls to a function lower to actual program function
+ /// calls.
+ ///
+ /// The idea is to test whether the program is likely to require a 'call'
+ /// instruction or equivalent in order to call the given function.
+ ///
+ /// FIXME: It's not clear that this is a good or useful query API. Client's
+ /// should probably move to simpler cost metrics using the above.
+ /// Alternatively, we could split the cost interface into distinct code-size
+ /// and execution-speed costs. This would allow modelling the core of this
+ /// query more accurately as the a call is a single small instruction, but
+ /// incurs significant execution cost.
+ virtual bool isLoweredToCall(const Function *F) const;
+
/// @}
/// \name Scalar Target Information
using namespace llvm;
-/// callIsSmall - If a call is likely to lower to a single target instruction,
-/// or is otherwise deemed small return true.
-/// TODO: Perhaps calls like memcpy, strcpy, etc?
-bool llvm::callIsSmall(ImmutableCallSite CS) {
- if (isa<IntrinsicInst>(CS.getInstruction()))
- return true;
-
- const Function *F = CS.getCalledFunction();
- if (!F) return false;
-
- if (F->hasLocalLinkage()) return false;
-
- if (!F->hasName()) return false;
-
- StringRef Name = F->getName();
-
- // These will all likely lower to a single selection DAG node.
- if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" ||
- Name == "fabs" || Name == "fabsf" || Name == "fabsl" ||
- Name == "sin" || Name == "sinf" || Name == "sinl" ||
- Name == "cos" || Name == "cosf" || Name == "cosl" ||
- Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl" )
- return true;
-
- // These are all likely to be optimized into something smaller.
- if (Name == "pow" || Name == "powf" || Name == "powl" ||
- Name == "exp2" || Name == "exp2l" || Name == "exp2f" ||
- Name == "floor" || Name == "floorf" || Name == "ceil" ||
- Name == "round" || Name == "ffs" || Name == "ffsl" ||
- Name == "abs" || Name == "labs" || Name == "llabs")
- return true;
-
- return false;
-}
-
/// analyzeBasicBlock - Fill in the current structure with information gleaned
/// from the specified block.
void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB,
unsigned NumInstsBeforeThisBB = NumInsts;
for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
II != E; ++II) {
- if (TargetTransformInfo::TCC_Free == TTI.getUserCost(&*II))
- continue;
-
// Special handling for calls.
if (isa<CallInst>(II) || isa<InvokeInst>(II)) {
ImmutableCallSite CS(cast<Instruction>(II));
// for that case.
if (F == BB->getParent())
isRecursive = true;
- }
-
- if (!callIsSmall(CS)) {
- // Each argument to a call takes on average one instruction to set up.
- NumInsts += CS.arg_size();
+ if (TTI.isLoweredToCall(F))
+ ++NumCalls;
+ } else {
// We don't want inline asm to count as a call - that would prevent loop
// unrolling. The argument setup cost is still real, though.
if (!isa<InlineAsm>(CS.getCalledValue()))
if (InvI->hasFnAttr(Attribute::NoDuplicate))
notDuplicatable = true;
- ++NumInsts;
+ NumInsts += TTI.getUserCost(&*II);
}
if (isa<ReturnInst>(BB->getTerminator()))
#include "llvm/IR/Instruction.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Instructions.h"
+#include "llvm/Support/CallSite.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
return PrevTTI->getGEPCost(Ptr, Operands);
}
+unsigned TargetTransformInfo::getCallCost(FunctionType *FTy,
+ int NumArgs) const {
+ return PrevTTI->getCallCost(FTy, NumArgs);
+}
+
+unsigned TargetTransformInfo::getCallCost(const Function *F,
+ int NumArgs) const {
+ return PrevTTI->getCallCost(F, NumArgs);
+}
+
+unsigned TargetTransformInfo::getCallCost(
+ const Function *F, ArrayRef<const Value *> Arguments) const {
+ return PrevTTI->getCallCost(F, Arguments);
+}
+
+unsigned TargetTransformInfo::getIntrinsicCost(
+ Intrinsic::ID IID, Type *RetTy, ArrayRef<Type *> ParamTys) const {
+ return PrevTTI->getIntrinsicCost(IID, RetTy, ParamTys);
+}
+
+unsigned TargetTransformInfo::getIntrinsicCost(
+ Intrinsic::ID IID, Type *RetTy, ArrayRef<const Value *> Arguments) const {
+ return PrevTTI->getIntrinsicCost(IID, RetTy, Arguments);
+}
+
unsigned TargetTransformInfo::getUserCost(const User *U) const {
return PrevTTI->getUserCost(U);
}
+bool TargetTransformInfo::isLoweredToCall(const Function *F) const {
+ return PrevTTI->isLoweredToCall(F);
+}
+
bool TargetTransformInfo::isLegalAddImmediate(int64_t Imm) const {
return PrevTTI->isLegalAddImmediate(Imm);
}
virtual void initializePass() {
// Note that this subclass is special, and must *not* call initializeTTI as
// it does not chain.
+ TopTTI = this;
PrevTTI = 0;
DL = getAnalysisIfAvailable<DataLayout>();
}
return TCC_Free;
}
+ unsigned getCallCost(FunctionType *FTy, int NumArgs = -1) const {
+ assert(FTy && "FunctionType must be provided to this routine.");
+
+ // The target-independent implementation just measures the size of the
+ // function by approximating that each argument will take on average one
+ // instruction to prepare.
+
+ if (NumArgs < 0)
+ // Set the argument number to the number of explicit arguments in the
+ // function.
+ NumArgs = FTy->getNumParams();
+
+ return TCC_Basic * (NumArgs + 1);
+ }
+
+ unsigned getCallCost(const Function *F, int NumArgs = -1) const {
+ assert(F && "A concrete function must be provided to this routine.");
+
+ if (NumArgs < 0)
+ // Set the argument number to the number of explicit arguments in the
+ // function.
+ NumArgs = F->arg_size();
+
+ if (Intrinsic::ID IID = (Intrinsic::ID)F->getIntrinsicID()) {
+ FunctionType *FTy = F->getFunctionType();
+ SmallVector<Type *, 8> ParamTys(FTy->param_begin(), FTy->param_end());
+ return TopTTI->getIntrinsicCost(IID, FTy->getReturnType(), ParamTys);
+ }
+
+ if (!TopTTI->isLoweredToCall(F))
+ return TCC_Basic; // Give a basic cost if it will be lowered directly.
+
+ return TopTTI->getCallCost(F->getFunctionType(), NumArgs);
+ }
+
+ unsigned getCallCost(const Function *F,
+ ArrayRef<const Value *> Arguments) const {
+ // Simply delegate to generic handling of the call.
+ // FIXME: We should use instsimplify or something else to catch calls which
+ // will constant fold with these arguments.
+ return TopTTI->getCallCost(F, Arguments.size());
+ }
+
+ unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy,
+ ArrayRef<Type *> ParamTys) const {
+ switch (IID) {
+ default:
+ // Intrinsics rarely (if ever) have normal argument setup constraints.
+ // Model them as having a basic instruction cost.
+ // FIXME: This is wrong for libc intrinsics.
+ return TCC_Basic;
+
+ case Intrinsic::dbg_declare:
+ case Intrinsic::dbg_value:
+ case Intrinsic::invariant_start:
+ case Intrinsic::invariant_end:
+ case Intrinsic::lifetime_start:
+ case Intrinsic::lifetime_end:
+ case Intrinsic::objectsize:
+ case Intrinsic::ptr_annotation:
+ case Intrinsic::var_annotation:
+ // These intrinsics don't actually represent code after lowering.
+ return TCC_Free;
+ }
+ }
+
+ unsigned getIntrinsicCost(Intrinsic::ID IID, Type *RetTy,
+ ArrayRef<const Value *> Arguments) const {
+ // Delegate to the generic intrinsic handling code. This mostly provides an
+ // opportunity for targets to (for example) special case the cost of
+ // certain intrinsics based on constants used as arguments.
+ SmallVector<Type *, 8> ParamTys;
+ ParamTys.reserve(Arguments.size());
+ for (unsigned Idx = 0, Size = Arguments.size(); Idx != Size; ++Idx)
+ ParamTys.push_back(Arguments[Idx]->getType());
+ return TopTTI->getIntrinsicCost(IID, RetTy, ParamTys);
+ }
+
unsigned getUserCost(const User *U) const {
if (isa<PHINode>(U))
return TCC_Free; // Model all PHI nodes as free.
// folded into their uses via addressing modes.
return GEP->hasAllConstantIndices() ? TCC_Free : TCC_Basic;
- // If we have a call of an intrinsic we can provide more detailed analysis
- // by inspecting the particular intrinsic called.
- // FIXME: Hoist this out into a getIntrinsicCost routine.
- if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(U)) {
- switch (II->getIntrinsicID()) {
- default:
- return TCC_Basic;
- case Intrinsic::dbg_declare:
- case Intrinsic::dbg_value:
- case Intrinsic::invariant_start:
- case Intrinsic::invariant_end:
- case Intrinsic::lifetime_start:
- case Intrinsic::lifetime_end:
- case Intrinsic::objectsize:
- case Intrinsic::ptr_annotation:
- case Intrinsic::var_annotation:
- // These intrinsics don't count as size.
- return TCC_Free;
+ if (ImmutableCallSite CS = U) {
+ const Function *F = CS.getCalledFunction();
+ if (!F) {
+ // Just use the called value type.
+ Type *FTy = CS.getCalledValue()->getType()->getPointerElementType();
+ return TopTTI->getCallCost(cast<FunctionType>(FTy), CS.arg_size());
}
+
+ SmallVector<const Value *, 8> Arguments;
+ for (ImmutableCallSite::arg_iterator AI = CS.arg_begin(),
+ AE = CS.arg_end();
+ AI != AE; ++AI)
+ Arguments.push_back(*AI);
+
+ return TopTTI->getCallCost(F, Arguments);
}
if (const CastInst *CI = dyn_cast<CastInst>(U)) {
U->getOperand(0)->getType() : 0);
}
+ bool isLoweredToCall(const Function *F) const {
+ // FIXME: These should almost certainly not be handled here, and instead
+ // handled with the help of TLI or the target itself. This was largely
+ // ported from existing analysis heuristics here so that such refactorings
+ // can take place in the future.
+
+ if (F->isIntrinsic())
+ return false;
+
+ if (F->hasLocalLinkage() || !F->hasName())
+ return true;
+
+ StringRef Name = F->getName();
+
+ // These will all likely lower to a single selection DAG node.
+ if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" ||
+ Name == "fabs" || Name == "fabsf" || Name == "fabsl" || Name == "sin" ||
+ Name == "sinf" || Name == "sinl" || Name == "cos" || Name == "cosf" ||
+ Name == "cosl" || Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl")
+ return false;
+
+ // These are all likely to be optimized into something smaller.
+ if (Name == "pow" || Name == "powf" || Name == "powl" || Name == "exp2" ||
+ Name == "exp2l" || Name == "exp2f" || Name == "floor" || Name ==
+ "floorf" || Name == "ceil" || Name == "round" || Name == "ffs" ||
+ Name == "ffsl" || Name == "abs" || Name == "labs" || Name == "llabs")
+ return false;
+
+ return true;
+ }
+
bool isLegalAddImmediate(int64_t Imm) const {
return false;
}
#include "llvm/Analysis/InlineCost.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/Loads.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
namespace {
struct TailCallElim : public FunctionPass {
+ const TargetTransformInfo *TTI;
+
static char ID; // Pass identification, replacement for typeid
TailCallElim() : FunctionPass(ID) {
initializeTailCallElimPass(*PassRegistry::getPassRegistry());
}
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+
virtual bool runOnFunction(Function &F);
private:
}
char TailCallElim::ID = 0;
-INITIALIZE_PASS(TailCallElim, "tailcallelim",
- "Tail Call Elimination", false, false)
+INITIALIZE_PASS_BEGIN(TailCallElim, "tailcallelim",
+ "Tail Call Elimination", false, false)
+INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
+INITIALIZE_PASS_END(TailCallElim, "tailcallelim",
+ "Tail Call Elimination", false, false)
// Public interface to the TailCallElimination pass
FunctionPass *llvm::createTailCallEliminationPass() {
return new TailCallElim();
}
+void TailCallElim::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<TargetTransformInfo>();
+}
+
/// AllocaMightEscapeToCalls - Return true if this alloca may be accessed by
/// callees of this function. We only do very simple analysis right now, this
/// could be expanded in the future to use mod/ref information for particular
// right, so don't even try to convert it...
if (F.getFunctionType()->isVarArg()) return false;
+ TTI = &getAnalysis<TargetTransformInfo>();
BasicBlock *OldEntry = 0;
bool TailCallsAreMarkedTail = false;
SmallVector<PHINode*, 8> ArgumentPHIs;
if (BB == &F->getEntryBlock() &&
FirstNonDbg(BB->front()) == CI &&
FirstNonDbg(llvm::next(BB->begin())) == TI &&
- callIsSmall(CI)) {
+ CI->getCalledFunction() &&
+ !TTI->isLoweredToCall(CI->getCalledFunction())) {
// A single-block function with just a call and a return. Check that
// the arguments match.
CallSite::arg_iterator I = CallSite(CI).arg_begin(),
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