if (TII->AnalyzeBranch(*this, TBB, FBB, Cond))
return NULL;
- // Avoid splitting backedges of loops. It would introduce small out-of-line
- // blocks into the loop which is very bad for code placement.
- if (this == Succ)
- return NULL;
- MachineLoopInfo *MLI = P->getAnalysisIfAvailable<MachineLoopInfo>();
- if (MLI->isLoopHeader(Succ))
- return NULL;
-
MachineBasicBlock *NMBB = MF->CreateMachineBasicBlock();
MF->insert(llvm::next(MachineFunction::iterator(this)), NMBB);
DEBUG(dbgs() << "Splitting critical edge:"
P->getAnalysisIfAvailable<MachineDominatorTree>())
MDT->addNewBlock(NMBB, this);
- if (MLI)
+ if (MachineLoopInfo *MLI = P->getAnalysisIfAvailable<MachineLoopInfo>())
if (MachineLoop *TIL = MLI->getLoopFor(this)) {
// If one or the other blocks were not in a loop, the new block is not
// either, and thus LI doesn't need to be updated.
bool llvm::PHIElimination::runOnMachineFunction(MachineFunction &MF) {
MRI = &MF.getRegInfo();
+ MLI = getAnalysisIfAvailable<MachineLoopInfo>();
bool Changed = false;
// We break edges when registers are live out from the predecessor block
// (not considering PHI nodes). If the register is live in to this block
// anyway, we would gain nothing from splitting.
- if (!LV.isLiveIn(Reg, MBB) && LV.isLiveOut(Reg, *PreMBB))
- Changed |= PreMBB->SplitCriticalEdge(&MBB, this) != 0;
+ // Avoid splitting backedges of loops. It would introduce small
+ // out-of-line blocks into the loop which is very bad for code placement.
+ if (PreMBB != &MBB &&
+ !LV.isLiveIn(Reg, MBB) && LV.isLiveOut(Reg, *PreMBB)) {
+ if (!(MLI->getLoopFor(PreMBB) == MLI->getLoopFor(&MBB) &&
+ MLI->isLoopHeader(&MBB)))
+ Changed |= PreMBB->SplitCriticalEdge(&MBB, this) != 0;
+ }
}
}
return true;
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineRegisterInfo.h"
namespace llvm {
class LiveVariables;
+ class MachineRegisterInfo;
+ class MachineLoopInfo;
/// Lower PHI instructions to copies.
class PHIElimination : public MachineFunctionPass {
- MachineRegisterInfo *MRI; // Machine register information
+ MachineRegisterInfo *MRI; // Machine register information
+ MachineLoopInfo *MLI;
public:
static char ID; // Pass identification, replacement for typeid