diff options
Diffstat (limited to 'llvm/lib/CodeGen/RegAllocFast.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/RegAllocFast.cpp | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/llvm/lib/CodeGen/RegAllocFast.cpp b/llvm/lib/CodeGen/RegAllocFast.cpp index cfee1a77..03411be 100644 --- a/llvm/lib/CodeGen/RegAllocFast.cpp +++ b/llvm/lib/CodeGen/RegAllocFast.cpp @@ -255,7 +255,7 @@ namespace { int getStackSpaceFor(Register VirtReg); void spill(MachineBasicBlock::iterator Before, Register VirtReg, - MCPhysReg AssignedReg, bool Kill); + MCPhysReg AssignedReg, bool Kill, bool LiveOut); void reload(MachineBasicBlock::iterator Before, Register VirtReg, MCPhysReg PhysReg); @@ -384,7 +384,7 @@ bool RegAllocFast::mayLiveIn(Register VirtReg) { /// Insert spill instruction for \p AssignedReg before \p Before. Update /// DBG_VALUEs with \p VirtReg operands with the stack slot. void RegAllocFast::spill(MachineBasicBlock::iterator Before, Register VirtReg, - MCPhysReg AssignedReg, bool Kill) { + MCPhysReg AssignedReg, bool Kill, bool LiveOut) { LLVM_DEBUG(dbgs() << "Spilling " << printReg(VirtReg, TRI) << " in " << printReg(AssignedReg, TRI)); int FI = getStackSpaceFor(VirtReg); @@ -394,6 +394,8 @@ void RegAllocFast::spill(MachineBasicBlock::iterator Before, Register VirtReg, TII->storeRegToStackSlot(*MBB, Before, AssignedReg, Kill, FI, &RC, TRI); ++NumStores; + MachineBasicBlock::iterator FirstTerm = MBB->getFirstTerminator(); + // When we spill a virtual register, we will have spill instructions behind // every definition of it, meaning we can switch all the DBG_VALUEs over // to just reference the stack slot. @@ -403,6 +405,17 @@ void RegAllocFast::spill(MachineBasicBlock::iterator Before, Register VirtReg, assert(NewDV->getParent() == MBB && "dangling parent pointer"); (void)NewDV; LLVM_DEBUG(dbgs() << "Inserting debug info due to spill:\n" << *NewDV); + + if (LiveOut) { + // We need to insert a DBG_VALUE at the end of the block if the spill slot + // is live out, but there is another use of the value after the + // spill. This will allow LiveDebugValues to see the correct live out + // value to propagate to the successors. + MachineInstr *ClonedDV = MBB->getParent()->CloneMachineInstr(NewDV); + MBB->insert(FirstTerm, ClonedDV); + LLVM_DEBUG(dbgs() << "Cloning debug info due to live out spill\n"); + } + // Rewrite unassigned dbg_values to use the stack slot. MachineOperand &MO = DBG->getOperand(0); if (MO.isReg() && MO.getReg() == 0) @@ -868,7 +881,7 @@ void RegAllocFast::defineVirtReg(MachineInstr &MI, unsigned OpNum, LLVM_DEBUG(dbgs() << "Spill Reason: LO: " << LRI->LiveOut << " RL: " << LRI->Reloaded << '\n'); bool Kill = LRI->LastUse == nullptr; - spill(SpillBefore, VirtReg, PhysReg, Kill); + spill(SpillBefore, VirtReg, PhysReg, Kill, LRI->LiveOut); LRI->LastUse = nullptr; } LRI->LiveOut = false; |