diff options
| -rw-r--r-- | lib/CodeGen/VirtRegMap.cpp | 32 |
1 files changed, 28 insertions, 4 deletions
diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp index e0aa405398..47772e7c02 100644 --- a/lib/CodeGen/VirtRegMap.cpp +++ b/lib/CodeGen/VirtRegMap.cpp @@ -21,6 +21,7 @@ #include "LiveDebugVariables.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/Statistic.h" +#include "llvm/ADT/SparseSet.h" #include "llvm/CodeGen/LiveIntervalAnalysis.h" #include "llvm/CodeGen/LiveStackAnalysis.h" #include "llvm/CodeGen/MachineFrameInfo.h" @@ -160,6 +161,7 @@ class VirtRegRewriter : public MachineFunctionPass { SlotIndexes *Indexes; LiveIntervals *LIS; VirtRegMap *VRM; + SparseSet<unsigned> PhysRegs; void rewrite(); void addMBBLiveIns(); @@ -267,6 +269,15 @@ void VirtRegRewriter::rewrite() { SmallVector<unsigned, 8> SuperKills; SmallPtrSet<const MachineInstr *, 4> NoReturnInsts; + // Here we have a SparseSet to hold which PhysRegs are actually encountered + // in the MF we are about to iterate over so that later when we call + // setPhysRegUsed, we are only doing it for physRegs that were actually found + // in the program and not for all of the possible physRegs for the given + // target architecture. If the target has a lot of physRegs, then for a small + // program there will be a significant compile time reduction here. + PhysRegs.clear(); + PhysRegs.setUniverse(TRI->getNumRegs()); + for (MachineFunction::iterator MBBI = MF->begin(), MBBE = MF->end(); MBBI != MBBE; ++MBBI) { DEBUG(MBBI->print(dbgs(), Indexes)); @@ -303,6 +314,15 @@ void VirtRegRewriter::rewrite() { if (MO.isRegMask()) MRI->addPhysRegsUsedFromRegMask(MO.getRegMask()); + // If we encounter a VirtReg or PhysReg then get at the PhysReg and add + // it to the physreg bitset. Later we use only the PhysRegs that were + // actually encountered in the MF to populate the MRI's used physregs. + if (MO.isReg() && MO.getReg()) + PhysRegs.insert( + TargetRegisterInfo::isVirtualRegister(MO.getReg()) ? + VRM->getPhys(MO.getReg()) : + MO.getReg()); + if (!MO.isReg() || !TargetRegisterInfo::isVirtualRegister(MO.getReg())) continue; unsigned VirtReg = MO.getReg(); @@ -376,11 +396,14 @@ void VirtRegRewriter::rewrite() { // Tell MRI about physical registers in use. if (NoReturnInsts.empty()) { - for (unsigned Reg = 1, RegE = TRI->getNumRegs(); Reg != RegE; ++Reg) - if (!MRI->reg_nodbg_empty(Reg)) - MRI->setPhysRegUsed(Reg); + for (SparseSet<unsigned>::iterator + RegI = PhysRegs.begin(), E = PhysRegs.end(); RegI != E; ++RegI) + if (!MRI->reg_nodbg_empty(*RegI)) + MRI->setPhysRegUsed(*RegI); } else { - for (unsigned Reg = 1, RegE = TRI->getNumRegs(); Reg != RegE; ++Reg) { + for (SparseSet<unsigned>::iterator + I = PhysRegs.begin(), E = PhysRegs.end(); I != E; ++I) { + unsigned Reg = *I; if (MRI->reg_nodbg_empty(Reg)) continue; // Check if this register has a use that will impact the rest of the @@ -397,3 +420,4 @@ void VirtRegRewriter::rewrite() { } } } + |