1 //===---- CGLoopInfo.cpp - LLVM CodeGen for loop metadata -*- C++ -*-------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "CGLoopInfo.h"
11 #include "llvm/IR/BasicBlock.h"
12 #include "llvm/IR/Constants.h"
13 #include "llvm/IR/InstrTypes.h"
14 #include "llvm/IR/Instructions.h"
15 #include "llvm/IR/Metadata.h"
16 using namespace clang;
17 using namespace CodeGen;
20 static MDNode *createMetadata(LLVMContext &Ctx, const LoopAttributes &Attrs) {
22 if (!Attrs.IsParallel && Attrs.VectorizerWidth == 0 &&
23 Attrs.VectorizerUnroll == 0 &&
24 Attrs.VectorizerEnable == LoopAttributes::VecUnspecified)
27 SmallVector<Metadata *, 4> Args;
28 // Reserve operand 0 for loop id self reference.
29 MDNode *TempNode = MDNode::getTemporary(Ctx, None);
30 Args.push_back(TempNode);
32 // Setting vectorizer.width
33 if (Attrs.VectorizerWidth > 0) {
34 Metadata *Vals[] = {MDString::get(Ctx, "llvm.loop.vectorize.width"),
35 ConstantAsMetadata::get(ConstantInt::get(
36 Type::getInt32Ty(Ctx), Attrs.VectorizerWidth))};
37 Args.push_back(MDNode::get(Ctx, Vals));
40 // Setting vectorizer.unroll
41 if (Attrs.VectorizerUnroll > 0) {
42 Metadata *Vals[] = {MDString::get(Ctx, "llvm.loop.interleave.count"),
43 ConstantAsMetadata::get(ConstantInt::get(
44 Type::getInt32Ty(Ctx), Attrs.VectorizerUnroll))};
45 Args.push_back(MDNode::get(Ctx, Vals));
48 // Setting vectorizer.enable
49 if (Attrs.VectorizerEnable != LoopAttributes::VecUnspecified) {
51 MDString::get(Ctx, "llvm.loop.vectorize.enable"),
52 ConstantAsMetadata::get(ConstantInt::get(
54 (Attrs.VectorizerEnable == LoopAttributes::VecEnable)))};
55 Args.push_back(MDNode::get(Ctx, Vals));
58 // Set the first operand to itself.
59 MDNode *LoopID = MDNode::get(Ctx, Args);
60 LoopID->replaceOperandWith(0, LoopID);
61 MDNode::deleteTemporary(TempNode);
65 LoopAttributes::LoopAttributes(bool IsParallel)
66 : IsParallel(IsParallel), VectorizerEnable(LoopAttributes::VecUnspecified),
67 VectorizerWidth(0), VectorizerUnroll(0) {}
69 void LoopAttributes::clear() {
73 VectorizerEnable = LoopAttributes::VecUnspecified;
76 LoopInfo::LoopInfo(BasicBlock *Header, const LoopAttributes &Attrs)
77 : LoopID(nullptr), Header(Header), Attrs(Attrs) {
78 LoopID = createMetadata(Header->getContext(), Attrs);
81 void LoopInfoStack::push(BasicBlock *Header) {
82 Active.push_back(LoopInfo(Header, StagedAttrs));
83 // Clear the attributes so nested loops do not inherit them.
87 void LoopInfoStack::pop() {
88 assert(!Active.empty() && "No active loops to pop");
92 void LoopInfoStack::InsertHelper(Instruction *I) const {
96 const LoopInfo &L = getInfo();
100 if (TerminatorInst *TI = dyn_cast<TerminatorInst>(I)) {
101 for (unsigned i = 0, ie = TI->getNumSuccessors(); i < ie; ++i)
102 if (TI->getSuccessor(i) == L.getHeader()) {
103 TI->setMetadata("llvm.loop", L.getLoopID());
109 if (L.getAttributes().IsParallel && I->mayReadOrWriteMemory())
110 I->setMetadata("llvm.mem.parallel_loop_access", L.getLoopID());