namespace {
class LoopAligner : public MachineFunctionPass {
- const TargetLowering *TLI;
-
public:
static char ID;
- LoopAligner() : MachineFunctionPass((intptr_t)&ID) {}
+ LoopAligner() : MachineFunctionPass(&ID) {}
virtual bool runOnMachineFunction(MachineFunction &MF);
virtual const char *getPassName() const { return "Loop aligner"; }
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<MachineLoopInfo>();
AU.addPreserved<MachineLoopInfo>();
+ AU.addPreservedID(MachineDominatorsID);
MachineFunctionPass::getAnalysisUsage(AU);
}
};
bool LoopAligner::runOnMachineFunction(MachineFunction &MF) {
const MachineLoopInfo *MLI = &getAnalysis<MachineLoopInfo>();
- if (MLI->begin() == MLI->end())
+ if (MLI->empty())
return false; // No loops.
- unsigned Align = MF.getTarget().getTargetLowering()->getPrefLoopAlignment();
+ const TargetLowering *TLI = MF.getTarget().getTargetLowering();
+ if (!TLI)
+ return false;
+
+ unsigned Align = TLI->getPrefLoopAlignment();
if (!Align)
return false; // Don't care about loop alignment.
+ const Function *F = MF.getFunction();
+ if (F->hasFnAttr(Attribute::OptimizeForSize))
+ return false;
+
for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
MachineBasicBlock *MBB = I;
- if (MLI->isLoopHeader(MBB))
+ if (MLI->isLoopHeader(MBB)) {
+ MachineBasicBlock *PredBB = prior(I);
+ if (MLI->getLoopFor(MBB) == MLI->getLoopFor(PredBB))
+ // If previously BB is in the same loop, don't align this BB. We want
+ // to prevent adding noop's inside a loop.
+ continue;
MBB->setAlignment(Align);
+ }
}
return true;