1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
//===- 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/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"),
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"),
clEnumValN(TargetTransformInfo::TCK_SizeAndLatency,
"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"),
cl::init(false));
#define CM_NAME "cost-model"
#define DEBUG_TYPE CM_NAME
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;
else
OS << "Cost Model: Invalid cost";
OS << " for instruction: " << Inst << "\n";
}
}
return PreservedAnalyses::all();
}
|
