diff options
Diffstat (limited to 'lib/Target/R600/SIMachineFunctionInfo.cpp')
-rw-r--r-- | lib/Target/R600/SIMachineFunctionInfo.cpp | 57 |
1 files changed, 48 insertions, 9 deletions
diff --git a/lib/Target/R600/SIMachineFunctionInfo.cpp b/lib/Target/R600/SIMachineFunctionInfo.cpp index ea04346..af60995 100644 --- a/lib/Target/R600/SIMachineFunctionInfo.cpp +++ b/lib/Target/R600/SIMachineFunctionInfo.cpp @@ -10,8 +10,11 @@ #include "SIMachineFunctionInfo.h" +#include "SIInstrInfo.h" #include "SIRegisterInfo.h" #include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/LLVMContext.h" #define MAX_LANES 64 @@ -26,21 +29,57 @@ SIMachineFunctionInfo::SIMachineFunctionInfo(const MachineFunction &MF) PSInputAddr(0), SpillTracker() { } -static unsigned createLaneVGPR(MachineRegisterInfo &MRI) { - return MRI.createVirtualRegister(&AMDGPU::VReg_32RegClass); +static unsigned createLaneVGPR(MachineRegisterInfo &MRI, MachineFunction *MF) { + unsigned VGPR = MRI.createVirtualRegister(&AMDGPU::VReg_32RegClass); + + // We need to add this register as live out for the function, in order to + // have the live range calculated directly. + // + // When register spilling begins, we have already calculated the live + // live intervals for all the registers. Since we are spilling SGPRs to + // VGPRs, we need to update the Lane VGPR's live interval every time we + // spill or restore a register. + // + // Unfortunately, there is no good way to update the live interval as + // the TargetInstrInfo callbacks for spilling and restoring don't give + // us access to the live interval information. + // + // We are lucky, though, because the InlineSpiller calls + // LiveRangeEdit::calculateRegClassAndHint() which iterates through + // all the new register that have been created when restoring a register + // and calls LiveIntervals::getInterval(), which creates and computes + // the live interval for the newly created register. However, once this + // live intervals is created, it doesn't change and since we usually reuse + // the Lane VGPR multiple times, this means any uses after the first aren't + // added to the live interval. + // + // To work around this, we add Lane VGPRs to the functions live out list, + // so that we can guarantee its live range will cover all of its uses. + + for (MachineBasicBlock &MBB : *MF) { + if (MBB.back().getOpcode() == AMDGPU::S_ENDPGM) { + MBB.back().addOperand(*MF, MachineOperand::CreateReg(VGPR, false, true)); + return VGPR; + } + } + MF->getFunction()->getContext().emitError( + "Could not found S_ENGPGM instrtuction."); + return VGPR; } -unsigned SIMachineFunctionInfo::RegSpillTracker::getNextLane(MachineRegisterInfo &MRI) { +unsigned SIMachineFunctionInfo::RegSpillTracker::reserveLanes( + MachineRegisterInfo &MRI, MachineFunction *MF, unsigned NumRegs) { + unsigned StartLane = CurrentLane; + CurrentLane += NumRegs; if (!LaneVGPR) { - LaneVGPR = createLaneVGPR(MRI); + LaneVGPR = createLaneVGPR(MRI, MF); } else { - CurrentLane++; - if (CurrentLane == MAX_LANES) { - CurrentLane = 0; - LaneVGPR = createLaneVGPR(MRI); + if (CurrentLane >= MAX_LANES) { + StartLane = CurrentLane = 0; + LaneVGPR = createLaneVGPR(MRI, MF); } } - return CurrentLane; + return StartLane; } void SIMachineFunctionInfo::RegSpillTracker::addSpilledReg(unsigned FrameIndex, |