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//===- CostModel.cpp ------ Cost Model Analysis ---------------------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file defines the cost model analysis. It provides a very basic cost
// estimation for LLVM-IR. This analysis uses the services of the codegen
// to approximate the cost of any IR instruction when lowered to machine
// instructions. The cost results are unit-less and the cost number represents
// the throughput of the machine assuming that all loads hit the cache, all
// branches are predicted, etc. The cost numbers can be added in order to
// compare two or more transformation alternatives.
#include "llvm/Analysis/CostModel.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/PassManager.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/IR/IntrinsicInst.h"
using namespace llvm;
static cl::opt<TargetTransformInfo::TargetCostKind> CostKind(
"cost-kind", cl::desc("Target cost kind"),
"throughput", "Reciprocal throughput"),
"latency", "Instruction latency"),
"code-size", "Code size"),
"size-latency", "Code size and latency")));
static cl::opt<bool> TypeBasedIntrinsicCost("type-based-intrinsic-cost",
cl::desc("Calculate intrinsics cost based only on argument types"),
#define CM_NAME "cost-model"
PreservedAnalyses CostModelPrinterPass::run(Function &F,
FunctionAnalysisManager &AM) {
auto &TTI = AM.getResult<TargetIRAnalysis>(F);
OS << "Printing analysis 'Cost Model Analysis' for function '" << F.getName() << "':\n";
for (BasicBlock &B : F) {
for (Instruction &Inst : B) {
// TODO: Use a pass parameter instead of cl::opt CostKind to determine
// which cost kind to print.
InstructionCost Cost;
auto *II = dyn_cast<IntrinsicInst>(&Inst);
if (II && TypeBasedIntrinsicCost) {
IntrinsicCostAttributes ICA(II->getIntrinsicID(), *II,
InstructionCost::getInvalid(), true);
Cost = TTI.getIntrinsicInstrCost(ICA, CostKind);
else {
Cost = TTI.getInstructionCost(&Inst, CostKind);
if (auto CostVal = Cost.getValue())
OS << "Cost Model: Found an estimated cost of " << *CostVal;
OS << "Cost Model: Invalid cost";
OS << " for instruction: " << Inst << "\n";
return PreservedAnalyses::all();