diff options
Diffstat (limited to 'lib/CodeGen/VirtRegMap.cpp')
| -rw-r--r-- | lib/CodeGen/VirtRegMap.cpp | 108 |
1 files changed, 70 insertions, 38 deletions
diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp index c6ac4b208d..ebdbb86c2b 100644 --- a/lib/CodeGen/VirtRegMap.cpp +++ b/lib/CodeGen/VirtRegMap.cpp @@ -242,10 +242,12 @@ namespace { /// blocks that have low register pressure (the vreg may be spilled due to /// register pressure in other blocks). class VISIBILITY_HIDDEN LocalSpiller : public Spiller { + SSARegMap *RegMap; const MRegisterInfo *MRI; const TargetInstrInfo *TII; public: bool runOnMachineFunction(MachineFunction &MF, VirtRegMap &VRM) { + RegMap = MF.getSSARegMap(); MRI = MF.getTarget().getRegisterInfo(); TII = MF.getTarget().getInstrInfo(); DOUT << "\n**** Local spiller rewriting function '" @@ -776,25 +778,33 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { if (!MO.isRegister() || MO.getReg() == 0) continue; // Ignore non-register operands. - if (MRegisterInfo::isPhysicalRegister(MO.getReg())) { + unsigned VirtReg = MO.getReg(); + if (MRegisterInfo::isPhysicalRegister(VirtReg)) { // Ignore physregs for spilling, but remember that it is used by this // function. - MF.setPhysRegUsed(MO.getReg()); - ReusedOperands.markClobbered(MO.getReg()); + MF.setPhysRegUsed(VirtReg); + ReusedOperands.markClobbered(VirtReg); continue; } - assert(MRegisterInfo::isVirtualRegister(MO.getReg()) && + assert(MRegisterInfo::isVirtualRegister(VirtReg) && "Not a virtual or a physical register?"); - unsigned VirtReg = MO.getReg(); + unsigned SubIdx = 0; + bool isSubReg = RegMap->isSubRegister(VirtReg); + if (isSubReg) { + SubIdx = RegMap->getSubRegisterIndex(VirtReg); + VirtReg = RegMap->getSuperRegister(VirtReg); + } + if (VRM.isAssignedReg(VirtReg)) { // This virtual register was assigned a physreg! unsigned Phys = VRM.getPhys(VirtReg); MF.setPhysRegUsed(Phys); if (MO.isDef()) ReusedOperands.markClobbered(Phys); - MI.getOperand(i).setReg(Phys); + unsigned RReg = isSubReg ? MRI->getSubReg(Phys, SubIdx) : Phys; + MI.getOperand(i).setReg(RReg); continue; } @@ -817,6 +827,24 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { if (ReuseSlot != VirtRegMap::NO_STACK_SLOT) PhysReg = Spills.getSpillSlotOrReMatPhysReg(ReuseSlot); } + + // If this is a sub-register use, make sure the reuse register is in the + // right register class. For example, for x86 not all of the 32-bit + // registers have accessible sub-registers. + // Similarly so for EXTRACT_SUBREG. Consider this: + // EDI = op + // MOV32_mr fi#1, EDI + // ... + // = EXTRACT_SUBREG fi#1 + // fi#1 is available in EDI, but it cannot be reused because it's not in + // the right register file. + if (PhysReg && + (isSubReg || MI.getOpcode() == TargetInstrInfo::EXTRACT_SUBREG)) { + const TargetRegisterClass* RC = RegMap->getRegClass(VirtReg); + if (!RC->contains(PhysReg)) + PhysReg = 0; + } + if (PhysReg) { // This spilled operand might be part of a two-address operand. If this // is the case, then changing it will necessarily require changing the @@ -824,6 +852,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { // aren't allowed to modify the reused register. If none of these cases // apply, reuse it. bool CanReuse = true; + int ti = TID->getOperandConstraint(i, TOI::TIED_TO); if (ti != -1 && MI.getOperand(ti).isRegister() && @@ -845,7 +874,8 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { << MRI->getName(PhysReg) << " for vreg" << VirtReg <<" instead of reloading into physreg " << MRI->getName(VRM.getPhys(VirtReg)) << "\n"; - MI.getOperand(i).setReg(PhysReg); + unsigned RReg = isSubReg ? MRI->getSubReg(PhysReg, SubIdx) : PhysReg; + MI.getOperand(i).setReg(RReg); // The only technical detail we have is that we don't know that // PhysReg won't be clobbered by a reloaded stack slot that occurs @@ -883,7 +913,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { } } continue; - } + } // CanReuse // Otherwise we have a situation where we have a two-address instruction // whose mod/ref operand needs to be reloaded. This reload is already @@ -917,13 +947,14 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { DOUT << " from physreg " << MRI->getName(PhysReg) << " for vreg" << VirtReg << " instead of reloading into same physreg.\n"; - MI.getOperand(i).setReg(PhysReg); + unsigned RReg = isSubReg ? MRI->getSubReg(PhysReg, SubIdx) : PhysReg; + MI.getOperand(i).setReg(RReg); ReusedOperands.markClobbered(PhysReg); ++NumReused; continue; } - const TargetRegisterClass* RC = MF.getSSARegMap()->getRegClass(VirtReg); + const TargetRegisterClass* RC = RegMap->getRegClass(VirtReg); MF.setPhysRegUsed(DesignatedReg); ReusedOperands.markClobbered(DesignatedReg); MRI->copyRegToReg(MBB, &MI, DesignatedReg, PhysReg, RC, RC); @@ -935,16 +966,17 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { Spills.ClobberPhysReg(DesignatedReg); Spills.addAvailable(ReuseSlot, &MI, DesignatedReg); - MI.getOperand(i).setReg(DesignatedReg); + unsigned RReg = + isSubReg ? MRI->getSubReg(DesignatedReg, SubIdx) : DesignatedReg; + MI.getOperand(i).setReg(RReg); DOUT << '\t' << *prior(MII); ++NumReused; continue; - } + } // is (PhysReg) // Otherwise, reload it and remember that we have it. PhysReg = VRM.getPhys(VirtReg); assert(PhysReg && "Must map virtreg to physreg!"); - const TargetRegisterClass* RC = MF.getSSARegMap()->getRegClass(VirtReg); // Note that, if we reused a register for a previous operand, the // register we want to reload into might not actually be @@ -960,6 +992,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { MRI->reMaterialize(MBB, &MI, PhysReg, VRM.getReMaterializedMI(VirtReg)); ++NumReMats; } else { + const TargetRegisterClass* RC = RegMap->getRegClass(VirtReg); MRI->loadRegFromStackSlot(MBB, &MI, PhysReg, SSorRMId, RC); ++NumLoads; } @@ -974,7 +1007,8 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { // unless it's a two-address operand. if (TID->getOperandConstraint(i, TOI::TIED_TO) == -1) MI.getOperand(i).setIsKill(); - MI.getOperand(i).setReg(PhysReg); + unsigned RReg = isSubReg ? MRI->getSubReg(PhysReg, SubIdx) : PhysReg; + MI.getOperand(i).setReg(RReg); UpdateKills(*prior(MII), RegKills, KillOps); DOUT << '\t' << *prior(MII); } @@ -1002,30 +1036,28 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { // straight load from the virt reg slot. if ((MR & VirtRegMap::isRef) && !(MR & VirtRegMap::isMod)) { int FrameIdx; - if (unsigned DestReg = TII->isLoadFromStackSlot(&MI, FrameIdx)) { - if (FrameIdx == SS) { - // If this spill slot is available, turn it into a copy (or nothing) - // instead of leaving it as a load! - if (unsigned InReg = Spills.getSpillSlotOrReMatPhysReg(SS)) { - DOUT << "Promoted Load To Copy: " << MI; - if (DestReg != InReg) { - const TargetRegisterClass *RC = - MF.getSSARegMap()->getRegClass(VirtReg); - MRI->copyRegToReg(MBB, &MI, DestReg, InReg, RC, RC); - // Revisit the copy so we make sure to notice the effects of the - // operation on the destreg (either needing to RA it if it's - // virtual or needing to clobber any values if it's physical). - NextMII = &MI; - --NextMII; // backtrack to the copy. - BackTracked = true; - } else - DOUT << "Removing now-noop copy: " << MI; + unsigned DestReg = TII->isLoadFromStackSlot(&MI, FrameIdx); + if (DestReg && FrameIdx == SS) { + // If this spill slot is available, turn it into a copy (or nothing) + // instead of leaving it as a load! + if (unsigned InReg = Spills.getSpillSlotOrReMatPhysReg(SS)) { + DOUT << "Promoted Load To Copy: " << MI; + if (DestReg != InReg) { + const TargetRegisterClass *RC = RegMap->getRegClass(VirtReg); + MRI->copyRegToReg(MBB, &MI, DestReg, InReg, RC, RC); + // Revisit the copy so we make sure to notice the effects of the + // operation on the destreg (either needing to RA it if it's + // virtual or needing to clobber any values if it's physical). + NextMII = &MI; + --NextMII; // backtrack to the copy. + BackTracked = true; + } else + DOUT << "Removing now-noop copy: " << MI; - VRM.RemoveFromFoldedVirtMap(&MI); - MBB.erase(&MI); - Erased = true; - goto ProcessNextInst; - } + VRM.RemoveFromFoldedVirtMap(&MI); + MBB.erase(&MI); + Erased = true; + goto ProcessNextInst; } } } @@ -1121,7 +1153,7 @@ void LocalSpiller::RewriteMBB(MachineBasicBlock &MBB, VirtRegMap &VRM) { // The only vregs left are stack slot definitions. int StackSlot = VRM.getStackSlot(VirtReg); - const TargetRegisterClass *RC = MF.getSSARegMap()->getRegClass(VirtReg); + const TargetRegisterClass *RC = RegMap->getRegClass(VirtReg); // If this def is part of a two-address operand, make sure to execute // the store from the correct physical register. |