mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-10-19 11:02:59 +02:00
ae65e281f3
to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
112 lines
3.8 KiB
C++
112 lines
3.8 KiB
C++
//===- CostModel.cpp ------ Cost Model Analysis ---------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt 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/ADT/STLExtras.h"
|
|
#include "llvm/Analysis/Passes.h"
|
|
#include "llvm/Analysis/TargetTransformInfo.h"
|
|
#include "llvm/IR/Function.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/Support/CommandLine.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
using namespace llvm;
|
|
|
|
static cl::opt<TargetTransformInfo::TargetCostKind> CostKind(
|
|
"cost-kind", cl::desc("Target cost kind"),
|
|
cl::init(TargetTransformInfo::TCK_RecipThroughput),
|
|
cl::values(clEnumValN(TargetTransformInfo::TCK_RecipThroughput,
|
|
"throughput", "Reciprocal throughput"),
|
|
clEnumValN(TargetTransformInfo::TCK_Latency,
|
|
"latency", "Instruction latency"),
|
|
clEnumValN(TargetTransformInfo::TCK_CodeSize,
|
|
"code-size", "Code size")));
|
|
|
|
#define CM_NAME "cost-model"
|
|
#define DEBUG_TYPE CM_NAME
|
|
|
|
namespace {
|
|
class CostModelAnalysis : public FunctionPass {
|
|
|
|
public:
|
|
static char ID; // Class identification, replacement for typeinfo
|
|
CostModelAnalysis() : FunctionPass(ID), F(nullptr), TTI(nullptr) {
|
|
initializeCostModelAnalysisPass(
|
|
*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
/// Returns the expected cost of the instruction.
|
|
/// Returns -1 if the cost is unknown.
|
|
/// Note, this method does not cache the cost calculation and it
|
|
/// can be expensive in some cases.
|
|
unsigned getInstructionCost(const Instruction *I) const {
|
|
return TTI->getInstructionCost(I, TargetTransformInfo::TCK_RecipThroughput);
|
|
}
|
|
|
|
private:
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override;
|
|
bool runOnFunction(Function &F) override;
|
|
void print(raw_ostream &OS, const Module*) const override;
|
|
|
|
/// The function that we analyze.
|
|
Function *F;
|
|
/// Target information.
|
|
const TargetTransformInfo *TTI;
|
|
};
|
|
} // End of anonymous namespace
|
|
|
|
// Register this pass.
|
|
char CostModelAnalysis::ID = 0;
|
|
static const char cm_name[] = "Cost Model Analysis";
|
|
INITIALIZE_PASS_BEGIN(CostModelAnalysis, CM_NAME, cm_name, false, true)
|
|
INITIALIZE_PASS_END (CostModelAnalysis, CM_NAME, cm_name, false, true)
|
|
|
|
FunctionPass *llvm::createCostModelAnalysisPass() {
|
|
return new CostModelAnalysis();
|
|
}
|
|
|
|
void
|
|
CostModelAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.setPreservesAll();
|
|
}
|
|
|
|
bool
|
|
CostModelAnalysis::runOnFunction(Function &F) {
|
|
this->F = &F;
|
|
auto *TTIWP = getAnalysisIfAvailable<TargetTransformInfoWrapperPass>();
|
|
TTI = TTIWP ? &TTIWP->getTTI(F) : nullptr;
|
|
|
|
return false;
|
|
}
|
|
|
|
void CostModelAnalysis::print(raw_ostream &OS, const Module*) const {
|
|
if (!F)
|
|
return;
|
|
|
|
for (BasicBlock &B : *F) {
|
|
for (Instruction &Inst : B) {
|
|
unsigned Cost = TTI->getInstructionCost(&Inst, CostKind);
|
|
if (Cost != (unsigned)-1)
|
|
OS << "Cost Model: Found an estimated cost of " << Cost;
|
|
else
|
|
OS << "Cost Model: Unknown cost";
|
|
|
|
OS << " for instruction: " << Inst << "\n";
|
|
}
|
|
}
|
|
}
|