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//===- MustExecute.cpp - Printer for isGuaranteedToExecute ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/LoopUtils.h"
using namespace llvm;
namespace {
struct MustExecutePrinter : public FunctionPass {
DenseMap<Value*, SmallVector<Loop*, 4> > MustExec;
SmallVector<Value *, 4> Ordering;
static char ID; // Pass identification, replacement for typeid
MustExecutePrinter() : FunctionPass(ID) {
initializeMustExecutePrinterPass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<LoopInfoWrapperPass>();
}
bool runOnFunction(Function &F) override;
void print(raw_ostream &OS, const Module * = nullptr) const override;
void releaseMemory() override {
MustExec.clear();
Ordering.clear();
}
};
}
char MustExecutePrinter::ID = 0;
INITIALIZE_PASS_BEGIN(MustExecutePrinter, "print-mustexecute",
"Instructions which execute on loop entry", false, true)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
INITIALIZE_PASS_END(MustExecutePrinter, "print-mustexecute",
"Instructions which execute on loop entry", false, true)
FunctionPass *llvm::createMustExecutePrinter() {
return new MustExecutePrinter();
}
bool isMustExecuteIn(Instruction &I, Loop *L, DominatorTree *DT) {
// TODO: move loop specific code to analysis
//LoopSafetyInfo LSI;
//computeLoopSafetyInfo(&LSI, L);
//return isGuaranteedToExecute(I, DT, L, &LSI);
return isGuaranteedToExecuteForEveryIteration(&I, L);
}
bool MustExecutePrinter::runOnFunction(Function &F) {
auto &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
for (auto &I: instructions(F)) {
Loop *L = LI.getLoopFor(I.getParent());
while (L) {
if (isMustExecuteIn(I, L, &DT)) {
if (!MustExec.count(&I))
Ordering.push_back(&I);
MustExec[&I].push_back(L);
}
L = L->getParentLoop();
};
}
return false;
}
void MustExecutePrinter::print(raw_ostream &OS, const Module *M) const {
OS << "The following are guaranteed to execute (for the respective loops):\n";
for (Value *V: Ordering) {
V->printAsOperand(OS);
auto NumLoops = MustExec.lookup(V).size();
if (NumLoops > 1)
OS << "\t(mustexec in " << NumLoops << " loops: ";
else
OS << "\t(mustexec in: ";
bool first = true;
for (const Loop *L : MustExec.lookup(V)) {
if (!first)
OS << ", ";
first = false;
OS << L->getHeader()->getName();
}
OS << ")\n";
}
OS << "\n";
}
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