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//===- NVPTXSplitBBatBar.cpp - Split BB at Barrier --*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// Split basic blocks so that a basic block that contains a barrier instruction
// only contains the barrier instruction.
//
//===----------------------------------------------------------------------===//
#include "NVPTXSplitBBatBar.h"
#include "NVPTXUtilities.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/Support/InstIterator.h"
using namespace llvm;
namespace llvm {
FunctionPass *createSplitBBatBarPass();
}
char NVPTXSplitBBatBar::ID = 0;
bool NVPTXSplitBBatBar::runOnFunction(Function &F) {
SmallVector<Instruction *, 4> SplitPoints;
bool changed = false;
// Collect all the split points in SplitPoints
for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
BasicBlock::iterator IB = BI->begin();
BasicBlock::iterator II = IB;
BasicBlock::iterator IE = BI->end();
// Skit the first intruction. No splitting is needed at this
// point even if this is a bar.
while (II != IE) {
if (IntrinsicInst *inst = dyn_cast<IntrinsicInst>(II)) {
Intrinsic::ID id = inst->getIntrinsicID();
// If this is a barrier, split at this instruction
// and the next instruction.
if (llvm::isBarrierIntrinsic(id)) {
if (II != IB)
SplitPoints.push_back(II);
II++;
if ((II != IE) && (!II->isTerminator())) {
SplitPoints.push_back(II);
II++;
}
continue;
}
}
II++;
}
}
for (unsigned i = 0; i != SplitPoints.size(); i++) {
changed = true;
Instruction *inst = SplitPoints[i];
inst->getParent()->splitBasicBlock(inst, "bar_split");
}
return changed;
}
// This interface will most likely not be necessary, because this pass will
// not be invoked by the driver, but will be used as a prerequisite to
// another pass.
FunctionPass *llvm::createSplitBBatBarPass() {
return new NVPTXSplitBBatBar();
}