From: Dan Gohman Date: Wed, 14 Apr 2010 16:51:49 +0000 (+0000) Subject: Move the code for emitting livein copies out of SelectionDAGISel. X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=98708260f55cab997a5db77e930a2bd35f4172aa;p=oota-llvm.git Move the code for emitting livein copies out of SelectionDAGISel. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101254 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h index 31da00d8e98..d312aaedca0 100644 --- a/include/llvm/CodeGen/MachineRegisterInfo.h +++ b/include/llvm/CodeGen/MachineRegisterInfo.h @@ -261,6 +261,12 @@ public: bool isLiveIn(unsigned Reg) const; bool isLiveOut(unsigned Reg) const; + /// EmitLiveInCopies - Emit copies to initialize livein virtual registers + /// into the given entry block. + void EmitLiveInCopies(MachineBasicBlock *EntryMBB, + const TargetRegisterInfo &TRI, + const TargetInstrInfo &TII); + private: void HandleVRegListReallocation(); diff --git a/lib/CodeGen/MachineRegisterInfo.cpp b/lib/CodeGen/MachineRegisterInfo.cpp index 8523c3648d5..6c0b454b13b 100644 --- a/lib/CodeGen/MachineRegisterInfo.cpp +++ b/lib/CodeGen/MachineRegisterInfo.cpp @@ -12,6 +12,8 @@ //===----------------------------------------------------------------------===// #include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Target/TargetInstrInfo.h" using namespace llvm; MachineRegisterInfo::MachineRegisterInfo(const TargetRegisterInfo &TRI) { @@ -144,6 +146,110 @@ bool MachineRegisterInfo::isLiveOut(unsigned Reg) const { return false; } +static cl::opt +SchedLiveInCopies("schedule-livein-copies", cl::Hidden, + cl::desc("Schedule copies of livein registers"), + cl::init(false)); + +/// EmitLiveInCopy - Emit a copy for a live in physical register. If the +/// physical register has only a single copy use, then coalesced the copy +/// if possible. +static void EmitLiveInCopy(MachineBasicBlock *MBB, + MachineBasicBlock::iterator &InsertPos, + unsigned VirtReg, unsigned PhysReg, + const TargetRegisterClass *RC, + DenseMap &CopyRegMap, + const MachineRegisterInfo &MRI, + const TargetRegisterInfo &TRI, + const TargetInstrInfo &TII) { + unsigned NumUses = 0; + MachineInstr *UseMI = NULL; + for (MachineRegisterInfo::use_iterator UI = MRI.use_begin(VirtReg), + UE = MRI.use_end(); UI != UE; ++UI) { + UseMI = &*UI; + if (++NumUses > 1) + break; + } + + // If the number of uses is not one, or the use is not a move instruction, + // don't coalesce. Also, only coalesce away a virtual register to virtual + // register copy. + bool Coalesced = false; + unsigned SrcReg, DstReg, SrcSubReg, DstSubReg; + if (NumUses == 1 && + TII.isMoveInstr(*UseMI, SrcReg, DstReg, SrcSubReg, DstSubReg) && + TargetRegisterInfo::isVirtualRegister(DstReg)) { + VirtReg = DstReg; + Coalesced = true; + } + + // Now find an ideal location to insert the copy. + MachineBasicBlock::iterator Pos = InsertPos; + while (Pos != MBB->begin()) { + MachineInstr *PrevMI = prior(Pos); + DenseMap::iterator RI = CopyRegMap.find(PrevMI); + // copyRegToReg might emit multiple instructions to do a copy. + unsigned CopyDstReg = (RI == CopyRegMap.end()) ? 0 : RI->second; + if (CopyDstReg && !TRI.regsOverlap(CopyDstReg, PhysReg)) + // This is what the BB looks like right now: + // r1024 = mov r0 + // ... + // r1 = mov r1024 + // + // We want to insert "r1025 = mov r1". Inserting this copy below the + // move to r1024 makes it impossible for that move to be coalesced. + // + // r1025 = mov r1 + // r1024 = mov r0 + // ... + // r1 = mov 1024 + // r2 = mov 1025 + break; // Woot! Found a good location. + --Pos; + } + + bool Emitted = TII.copyRegToReg(*MBB, Pos, VirtReg, PhysReg, RC, RC); + assert(Emitted && "Unable to issue a live-in copy instruction!\n"); + (void) Emitted; + + CopyRegMap.insert(std::make_pair(prior(Pos), VirtReg)); + if (Coalesced) { + if (&*InsertPos == UseMI) ++InsertPos; + MBB->erase(UseMI); + } +} + +/// EmitLiveInCopies - Emit copies to initialize livein virtual registers +/// into the given entry block. +void +MachineRegisterInfo::EmitLiveInCopies(MachineBasicBlock *EntryMBB, + const TargetRegisterInfo &TRI, + const TargetInstrInfo &TII) { + if (SchedLiveInCopies) { + // Emit the copies at a heuristically-determined location in the block. + DenseMap CopyRegMap; + MachineBasicBlock::iterator InsertPos = EntryMBB->begin(); + for (MachineRegisterInfo::livein_iterator LI = livein_begin(), + E = livein_end(); LI != E; ++LI) + if (LI->second) { + const TargetRegisterClass *RC = getRegClass(LI->second); + EmitLiveInCopy(EntryMBB, InsertPos, LI->second, LI->first, + RC, CopyRegMap, *this, TRI, TII); + } + } else { + // Emit the copies into the top of the block. + for (MachineRegisterInfo::livein_iterator LI = livein_begin(), + E = livein_end(); LI != E; ++LI) + if (LI->second) { + const TargetRegisterClass *RC = getRegClass(LI->second); + bool Emitted = TII.copyRegToReg(*EntryMBB, EntryMBB->begin(), + LI->second, LI->first, RC, RC); + assert(Emitted && "Unable to issue a live-in copy instruction!\n"); + (void) Emitted; + } + } +} + #ifndef NDEBUG void MachineRegisterInfo::dumpUses(unsigned Reg) const { for (use_iterator I = use_begin(Reg), E = use_end(); I != E; ++I) diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index 6067b1fded3..394ef82d721 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -69,10 +69,6 @@ EnableFastISelVerbose("fast-isel-verbose", cl::Hidden, static cl::opt EnableFastISelAbort("fast-isel-abort", cl::Hidden, cl::desc("Enable abort calls when \"fast\" instruction fails")); -static cl::opt -SchedLiveInCopies("schedule-livein-copies", cl::Hidden, - cl::desc("Schedule copies of livein registers"), - cl::init(false)); #ifndef NDEBUG static cl::opt @@ -173,106 +169,6 @@ MachineBasicBlock *TargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI, return 0; } -/// EmitLiveInCopy - Emit a copy for a live in physical register. If the -/// physical register has only a single copy use, then coalesced the copy -/// if possible. -static void EmitLiveInCopy(MachineBasicBlock *MBB, - MachineBasicBlock::iterator &InsertPos, - unsigned VirtReg, unsigned PhysReg, - const TargetRegisterClass *RC, - DenseMap &CopyRegMap, - const MachineRegisterInfo &MRI, - const TargetRegisterInfo &TRI, - const TargetInstrInfo &TII) { - unsigned NumUses = 0; - MachineInstr *UseMI = NULL; - for (MachineRegisterInfo::use_iterator UI = MRI.use_begin(VirtReg), - UE = MRI.use_end(); UI != UE; ++UI) { - UseMI = &*UI; - if (++NumUses > 1) - break; - } - - // If the number of uses is not one, or the use is not a move instruction, - // don't coalesce. Also, only coalesce away a virtual register to virtual - // register copy. - bool Coalesced = false; - unsigned SrcReg, DstReg, SrcSubReg, DstSubReg; - if (NumUses == 1 && - TII.isMoveInstr(*UseMI, SrcReg, DstReg, SrcSubReg, DstSubReg) && - TargetRegisterInfo::isVirtualRegister(DstReg)) { - VirtReg = DstReg; - Coalesced = true; - } - - // Now find an ideal location to insert the copy. - MachineBasicBlock::iterator Pos = InsertPos; - while (Pos != MBB->begin()) { - MachineInstr *PrevMI = prior(Pos); - DenseMap::iterator RI = CopyRegMap.find(PrevMI); - // copyRegToReg might emit multiple instructions to do a copy. - unsigned CopyDstReg = (RI == CopyRegMap.end()) ? 0 : RI->second; - if (CopyDstReg && !TRI.regsOverlap(CopyDstReg, PhysReg)) - // This is what the BB looks like right now: - // r1024 = mov r0 - // ... - // r1 = mov r1024 - // - // We want to insert "r1025 = mov r1". Inserting this copy below the - // move to r1024 makes it impossible for that move to be coalesced. - // - // r1025 = mov r1 - // r1024 = mov r0 - // ... - // r1 = mov 1024 - // r2 = mov 1025 - break; // Woot! Found a good location. - --Pos; - } - - bool Emitted = TII.copyRegToReg(*MBB, Pos, VirtReg, PhysReg, RC, RC); - assert(Emitted && "Unable to issue a live-in copy instruction!\n"); - (void) Emitted; - - CopyRegMap.insert(std::make_pair(prior(Pos), VirtReg)); - if (Coalesced) { - if (&*InsertPos == UseMI) ++InsertPos; - MBB->erase(UseMI); - } -} - -/// EmitLiveInCopies - If this is the first basic block in the function, -/// and if it has live ins that need to be copied into vregs, emit the -/// copies into the block. -static void EmitLiveInCopies(MachineBasicBlock *EntryMBB, - const MachineRegisterInfo &MRI, - const TargetRegisterInfo &TRI, - const TargetInstrInfo &TII) { - if (SchedLiveInCopies) { - // Emit the copies at a heuristically-determined location in the block. - DenseMap CopyRegMap; - MachineBasicBlock::iterator InsertPos = EntryMBB->begin(); - for (MachineRegisterInfo::livein_iterator LI = MRI.livein_begin(), - E = MRI.livein_end(); LI != E; ++LI) - if (LI->second) { - const TargetRegisterClass *RC = MRI.getRegClass(LI->second); - EmitLiveInCopy(EntryMBB, InsertPos, LI->second, LI->first, - RC, CopyRegMap, MRI, TRI, TII); - } - } else { - // Emit the copies into the top of the block. - for (MachineRegisterInfo::livein_iterator LI = MRI.livein_begin(), - E = MRI.livein_end(); LI != E; ++LI) - if (LI->second) { - const TargetRegisterClass *RC = MRI.getRegClass(LI->second); - bool Emitted = TII.copyRegToReg(*EntryMBB, EntryMBB->begin(), - LI->second, LI->first, RC, RC); - assert(Emitted && "Unable to issue a live-in copy instruction!\n"); - (void) Emitted; - } - } -} - //===----------------------------------------------------------------------===// // SelectionDAGISel code //===----------------------------------------------------------------------===// @@ -337,7 +233,7 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) { // If the first basic block in the function has live ins that need to be // copied into vregs, emit the copies into the top of the block before // emitting the code for the block. - EmitLiveInCopies(MF->begin(), *RegInfo, TRI, TII); + RegInfo->EmitLiveInCopies(MF->begin(), TRI, TII); // Add function live-ins to entry block live-in set. for (MachineRegisterInfo::livein_iterator I = RegInfo->livein_begin(),