diff options
| -rw-r--r-- | lib/CodeGen/MachineLICM.cpp | 30 |
1 files changed, 4 insertions, 26 deletions
diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp index 92c84f3e83..5580ec13f4 100644 --- a/lib/CodeGen/MachineLICM.cpp +++ b/lib/CodeGen/MachineLICM.cpp @@ -252,32 +252,6 @@ bool MachineLICM::IsLoopInvariantInst(MachineInstr &I) { return false; } - DEBUG({ - dbgs() << "--- Checking if we can hoist " << I; - if (I.getDesc().getImplicitUses()) { - dbgs() << " * Instruction has implicit uses:\n"; - - const TargetRegisterInfo *TRI = TM->getRegisterInfo(); - for (const unsigned *ImpUses = I.getDesc().getImplicitUses(); - *ImpUses; ++ImpUses) - dbgs() << " -> " << TRI->getName(*ImpUses) << "\n"; - } - - if (I.getDesc().getImplicitDefs()) { - dbgs() << " * Instruction has implicit defines:\n"; - - const TargetRegisterInfo *TRI = TM->getRegisterInfo(); - for (const unsigned *ImpDefs = I.getDesc().getImplicitDefs(); - *ImpDefs; ++ImpDefs) - dbgs() << " -> " << TRI->getName(*ImpDefs) << "\n"; - } - }); - - if (I.getDesc().getImplicitDefs() || I.getDesc().getImplicitUses()) { - DEBUG(dbgs() << "Cannot hoist with implicit defines or uses\n"); - return false; - } - // The instruction is loop invariant if all of its operands are. for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) { const MachineOperand &MO = I.getOperand(i); @@ -311,6 +285,10 @@ bool MachineLICM::IsLoopInvariantInst(MachineInstr &I) { } else if (!MO.isDead()) { // A def that isn't dead. We can't move it. return false; + } else if (CurLoop->getHeader()->isLiveIn(Reg)) { + // If the reg is live into the loop, we can't hoist an instruction + // which would clobber it. + return false; } } |