From 81218aa90e89bb0eb9d21d554a7f03a19f6cbe0e Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Tue, 13 Oct 2009 18:37:20 +0000 Subject: [PATCH] Commit the removal of this file, which is now moved to lib/Analysis. llvm-svn: 83999 --- lib/Transforms/Utils/InlineCost.cpp | 337 ---------------------------- 1 file changed, 337 deletions(-) delete mode 100644 lib/Transforms/Utils/InlineCost.cpp diff --git a/lib/Transforms/Utils/InlineCost.cpp b/lib/Transforms/Utils/InlineCost.cpp deleted file mode 100644 index ebb3920ba1b..00000000000 --- a/lib/Transforms/Utils/InlineCost.cpp +++ /dev/null @@ -1,337 +0,0 @@ -//===- InlineCost.cpp - Cost analysis for inliner -------------------------===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements inline cost analysis. -// -//===----------------------------------------------------------------------===// - -#include "llvm/Transforms/Utils/InlineCost.h" -#include "llvm/Support/CallSite.h" -#include "llvm/CallingConv.h" -#include "llvm/IntrinsicInst.h" -#include "llvm/ADT/SmallPtrSet.h" -using namespace llvm; - -// CountCodeReductionForConstant - Figure out an approximation for how many -// instructions will be constant folded if the specified value is constant. -// -unsigned InlineCostAnalyzer::RegionInfo:: - CountCodeReductionForConstant(Value *V) { - unsigned Reduction = 0; - for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E; ++UI) - if (isa(*UI)) - Reduction += 40; // Eliminating a conditional branch is a big win - else if (SwitchInst *SI = dyn_cast(*UI)) - // Eliminating a switch is a big win, proportional to the number of edges - // deleted. - Reduction += (SI->getNumSuccessors()-1) * 40; - else if (CallInst *CI = dyn_cast(*UI)) { - // Turning an indirect call into a direct call is a BIG win - Reduction += CI->getCalledValue() == V ? 500 : 0; - } else if (InvokeInst *II = dyn_cast(*UI)) { - // Turning an indirect call into a direct call is a BIG win - Reduction += II->getCalledValue() == V ? 500 : 0; - } else { - // Figure out if this instruction will be removed due to simple constant - // propagation. - Instruction &Inst = cast(**UI); - - // We can't constant propagate instructions which have effects or - // read memory. - // - // FIXME: It would be nice to capture the fact that a load from a - // pointer-to-constant-global is actually a *really* good thing to zap. - // Unfortunately, we don't know the pointer that may get propagated here, - // so we can't make this decision. - if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() || - isa(Inst)) - continue; - - bool AllOperandsConstant = true; - for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i) - if (!isa(Inst.getOperand(i)) && Inst.getOperand(i) != V) { - AllOperandsConstant = false; - break; - } - - if (AllOperandsConstant) { - // We will get to remove this instruction... - Reduction += 7; - - // And any other instructions that use it which become constants - // themselves. - Reduction += CountCodeReductionForConstant(&Inst); - } - } - - return Reduction; -} - -// CountCodeReductionForAlloca - Figure out an approximation of how much smaller -// the function will be if it is inlined into a context where an argument -// becomes an alloca. -// -unsigned InlineCostAnalyzer::RegionInfo:: - CountCodeReductionForAlloca(Value *V) { - if (!isa(V->getType())) return 0; // Not a pointer - unsigned Reduction = 0; - for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){ - Instruction *I = cast(*UI); - if (isa(I) || isa(I)) - Reduction += 10; - else if (GetElementPtrInst *GEP = dyn_cast(I)) { - // If the GEP has variable indices, we won't be able to do much with it. - if (!GEP->hasAllConstantIndices()) - Reduction += CountCodeReductionForAlloca(GEP)+15; - } else { - // If there is some other strange instruction, we're not going to be able - // to do much if we inline this. - return 0; - } - } - - return Reduction; -} - -/// analyzeBasicBlock - Fill in the current structure with information gleaned -/// from the specified block. -void InlineCostAnalyzer::RegionInfo::analyzeBasicBlock(const BasicBlock *BB) { - ++NumBlocks; - - for (BasicBlock::const_iterator II = BB->begin(), E = BB->end(); - II != E; ++II) { - if (isa(II)) continue; // PHI nodes don't count. - - // Special handling for calls. - if (isa(II) || isa(II)) { - if (isa(II)) - continue; // Debug intrinsics don't count as size. - - CallSite CS = CallSite::get(const_cast(&*II)); - - // If this function contains a call to setjmp or _setjmp, never inline - // it. This is a hack because we depend on the user marking their local - // variables as volatile if they are live across a setjmp call, and they - // probably won't do this in callers. - if (Function *F = CS.getCalledFunction()) - if (F->isDeclaration() && - (F->getName() == "setjmp" || F->getName() == "_setjmp")) { - NeverInline = true; - return; - } - - // Calls often compile into many machine instructions. Bump up their - // cost to reflect this. - if (!isa(II)) - NumInsts += InlineConstants::CallPenalty; - } - - // These, too, are calls. - if (isa(II) || isa(II)) - NumInsts += InlineConstants::CallPenalty; - - if (const AllocaInst *AI = dyn_cast(II)) { - if (!AI->isStaticAlloca()) - this->usesDynamicAlloca = true; - } - - if (isa(II) || isa(II->getType())) - ++NumVectorInsts; - - // Noop casts, including ptr <-> int, don't count. - if (const CastInst *CI = dyn_cast(II)) { - if (CI->isLosslessCast() || isa(CI) || - isa(CI)) - continue; - } else if (const GetElementPtrInst *GEPI = - dyn_cast(II)) { - // If a GEP has all constant indices, it will probably be folded with - // a load/store. - if (GEPI->hasAllConstantIndices()) - continue; - } - - if (isa(II)) - ++NumRets; - - ++NumInsts; - } -} - -/// analyzeFunction - Fill in the current structure with information gleaned -/// from the specified function. -void InlineCostAnalyzer::RegionInfo::analyzeFunction(Function *F) { - // Look at the size of the callee. Each basic block counts as 20 units, and - // each instruction counts as 5. - for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB) - analyzeBasicBlock(&*BB); - - // A function with exactly one return has it removed during the inlining - // process (see InlineFunction), so don't count it. - // FIXME: This knowledge should really be encoded outside of RegionInfo. - if (NumRets==1) - --NumInsts; - - // Check out all of the arguments to the function, figuring out how much - // code can be eliminated if one of the arguments is a constant. - for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I) - ArgumentWeights.push_back(ArgInfo(CountCodeReductionForConstant(I), - CountCodeReductionForAlloca(I))); -} - - - -// getInlineCost - The heuristic used to determine if we should inline the -// function call or not. -// -InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS, - SmallPtrSet &NeverInline) { - Instruction *TheCall = CS.getInstruction(); - Function *Callee = CS.getCalledFunction(); - Function *Caller = TheCall->getParent()->getParent(); - - // Don't inline functions which can be redefined at link-time to mean - // something else. Don't inline functions marked noinline. - if (Callee->mayBeOverridden() || - Callee->hasFnAttr(Attribute::NoInline) || NeverInline.count(Callee)) - return llvm::InlineCost::getNever(); - - // InlineCost - This value measures how good of an inline candidate this call - // site is to inline. A lower inline cost make is more likely for the call to - // be inlined. This value may go negative. - // - int InlineCost = 0; - - // If there is only one call of the function, and it has internal linkage, - // make it almost guaranteed to be inlined. - // - if (Callee->hasLocalLinkage() && Callee->hasOneUse()) - InlineCost += InlineConstants::LastCallToStaticBonus; - - // If this function uses the coldcc calling convention, prefer not to inline - // it. - if (Callee->getCallingConv() == CallingConv::Cold) - InlineCost += InlineConstants::ColdccPenalty; - - // If the instruction after the call, or if the normal destination of the - // invoke is an unreachable instruction, the function is noreturn. As such, - // there is little point in inlining this. - if (InvokeInst *II = dyn_cast(TheCall)) { - if (isa(II->getNormalDest()->begin())) - InlineCost += InlineConstants::NoreturnPenalty; - } else if (isa(++BasicBlock::iterator(TheCall))) - InlineCost += InlineConstants::NoreturnPenalty; - - // Get information about the callee... - RegionInfo &CalleeFI = CachedFunctionInfo[Callee]; - - // If we haven't calculated this information yet, do so now. - if (CalleeFI.NumBlocks == 0) - CalleeFI.analyzeFunction(Callee); - - // If we should never inline this, return a huge cost. - if (CalleeFI.NeverInline) - return InlineCost::getNever(); - - // FIXME: It would be nice to kill off CalleeFI.NeverInline. Then we - // could move this up and avoid computing the RegionInfo for - // things we are going to just return always inline for. This - // requires handling setjmp somewhere else, however. - if (!Callee->isDeclaration() && Callee->hasFnAttr(Attribute::AlwaysInline)) - return InlineCost::getAlways(); - - if (CalleeFI.usesDynamicAlloca) { - // Get infomation about the caller... - RegionInfo &CallerFI = CachedFunctionInfo[Caller]; - - // If we haven't calculated this information yet, do so now. - if (CallerFI.NumBlocks == 0) - CallerFI.analyzeFunction(Caller); - - // Don't inline a callee with dynamic alloca into a caller without them. - // Functions containing dynamic alloca's are inefficient in various ways; - // don't create more inefficiency. - if (!CallerFI.usesDynamicAlloca) - return InlineCost::getNever(); - } - - // Add to the inline quality for properties that make the call valuable to - // inline. This includes factors that indicate that the result of inlining - // the function will be optimizable. Currently this just looks at arguments - // passed into the function. - // - unsigned ArgNo = 0; - for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); - I != E; ++I, ++ArgNo) { - // Each argument passed in has a cost at both the caller and the callee - // sides. This favors functions that take many arguments over functions - // that take few arguments. - InlineCost -= 20; - - // If this is a function being passed in, it is very likely that we will be - // able to turn an indirect function call into a direct function call. - if (isa(I)) - InlineCost -= 100; - - // If an alloca is passed in, inlining this function is likely to allow - // significant future optimization possibilities (like scalar promotion, and - // scalarization), so encourage the inlining of the function. - // - else if (isa(I)) { - if (ArgNo < CalleeFI.ArgumentWeights.size()) - InlineCost -= CalleeFI.ArgumentWeights[ArgNo].AllocaWeight; - - // If this is a constant being passed into the function, use the argument - // weights calculated for the callee to determine how much will be folded - // away with this information. - } else if (isa(I)) { - if (ArgNo < CalleeFI.ArgumentWeights.size()) - InlineCost -= CalleeFI.ArgumentWeights[ArgNo].ConstantWeight; - } - } - - // Now that we have considered all of the factors that make the call site more - // likely to be inlined, look at factors that make us not want to inline it. - - // Don't inline into something too big, which would make it bigger. - // "size" here is the number of basic blocks, not instructions. - // - InlineCost += Caller->size()/15; - - // Look at the size of the callee. Each instruction counts as 5. - InlineCost += CalleeFI.NumInsts*5; - - return llvm::InlineCost::get(InlineCost); -} - -// getInlineFudgeFactor - Return a > 1.0 factor if the inliner should use a -// higher threshold to determine if the function call should be inlined. -float InlineCostAnalyzer::getInlineFudgeFactor(CallSite CS) { - Function *Callee = CS.getCalledFunction(); - - // Get information about the callee... - RegionInfo &CalleeFI = CachedFunctionInfo[Callee]; - - // If we haven't calculated this information yet, do so now. - if (CalleeFI.NumBlocks == 0) - CalleeFI.analyzeFunction(Callee); - - float Factor = 1.0f; - // Single BB functions are often written to be inlined. - if (CalleeFI.NumBlocks == 1) - Factor += 0.5f; - - // Be more aggressive if the function contains a good chunk (if it mades up - // at least 10% of the instructions) of vector instructions. - if (CalleeFI.NumVectorInsts > CalleeFI.NumInsts/2) - Factor += 2.0f; - else if (CalleeFI.NumVectorInsts > CalleeFI.NumInsts/10) - Factor += 1.5f; - return Factor; -}