#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachinePostDominators.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
class MachineSinking : public MachineFunctionPass {
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
- MachineRegisterInfo *MRI; // Machine register information
- MachineDominatorTree *DT; // Machine dominator tree
+ MachineRegisterInfo *MRI; // Machine register information
+ MachineDominatorTree *DT; // Machine dominator tree
+ MachinePostDominatorTree *PDT; // Machine post dominator tree
MachineLoopInfo *LI;
const MachineBlockFrequencyInfo *MBFI;
AliasAnalysis *AA;
MachineFunctionPass::getAnalysisUsage(AU);
AU.addRequired<AliasAnalysis>();
AU.addRequired<MachineDominatorTree>();
+ AU.addRequired<MachinePostDominatorTree>();
AU.addRequired<MachineLoopInfo>();
AU.addPreserved<MachineDominatorTree>();
+ AU.addPreserved<MachinePostDominatorTree>();
AU.addPreserved<MachineLoopInfo>();
if (UseBlockFreqInfo)
AU.addRequired<MachineBlockFrequencyInfo>();
TRI = MF.getSubtarget().getRegisterInfo();
MRI = &MF.getRegInfo();
DT = &getAnalysis<MachineDominatorTree>();
+ PDT = &getAnalysis<MachinePostDominatorTree>();
LI = &getAnalysis<MachineLoopInfo>();
MBFI = UseBlockFreqInfo ? &getAnalysis<MachineBlockFrequencyInfo>() : nullptr;
AA = &getAnalysis<AliasAnalysis>();
}
}
-/// isPostDominatedBy - Return true if A is post dominated by B.
-static bool isPostDominatedBy(MachineBasicBlock *A, MachineBasicBlock *B) {
-
- // FIXME - Use real post dominator.
- if (A->succ_size() != 2)
- return false;
- MachineBasicBlock::succ_iterator I = A->succ_begin();
- if (B == *I)
- ++I;
- MachineBasicBlock *OtherSuccBlock = *I;
- if (OtherSuccBlock->succ_size() != 1 ||
- *(OtherSuccBlock->succ_begin()) != B)
- return false;
-
- return true;
-}
-
/// isProfitableToSinkTo - Return true if it is profitable to sink MI.
bool MachineSinking::isProfitableToSinkTo(unsigned Reg, MachineInstr *MI,
MachineBasicBlock *MBB,
return false;
// It is profitable if SuccToSinkTo does not post dominate current block.
- if (!isPostDominatedBy(MBB, SuccToSinkTo))
- return true;
+ if (!PDT->dominates(SuccToSinkTo, MBB))
+ return true;
+
+ // It is profitable to sink an instruction from a deeper loop to a shallower
+ // loop, even if the latter post-dominates the former (PR21115).
+ if (LI->getLoopDepth(MBB) > LI->getLoopDepth(SuccToSinkTo))
+ return true;
// Check if only use in post dominated block is PHI instruction.
bool NonPHIUse = false;