Turn neon reg-reg moves fixup code into separate pass. This should reduce the compile time.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85850 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARM.h

@@ -105,6 +105,7 @@ FunctionPass *createARMObjectCodeEmitterPass(ARMBaseTargetMachine &TM,
 FunctionPass *createARMLoadStoreOptimizationPass(bool PreAlloc = false);
 FunctionPass *createARMConstantIslandPass();
 FunctionPass *createNEONPreAllocPass();
+FunctionPass *createNEONMoveFixPass();
 FunctionPass *createThumb2ITBlockPass();
 FunctionPass *createThumb2SizeReductionPass();
 

lib/Target/ARM/ARMBaseInstrInfo.cpp

@@ -658,39 +658,8 @@ ARMBaseInstrInfo::copyRegToReg(MachineBasicBlock &MBB,
     // Always use neon reg-reg move if source or dest is NEON-only regclass.
     BuildMI(MBB, I, DL, get(ARM::VMOVD), DestReg).addReg(SrcReg);
   } else if (DestRC == ARM::DPRRegisterClass) {
-    const ARMBaseRegisterInfo* TRI = &getRegisterInfo();
-
-    // If we do not found an instruction defining the reg, this means the
-    // register should be live-in for this BB. It's always to better to use
-    // NEON reg-reg moves.
-    unsigned Domain = ARMII::DomainNEON;
-    
-    // Find the Machine Instruction which defines SrcReg.
-    if (!MBB.empty()) {
-      MachineBasicBlock::iterator J = (I == MBB.begin() ? I : prior(I));
-      while (J != MBB.begin()) {
-        if (J->modifiesRegister(SrcReg, TRI))
-          break;
-        --J;
-      }
-
-      if (J->modifiesRegister(SrcReg, TRI)) {
-        Domain = J->getDesc().TSFlags & ARMII::DomainMask;
-        // Instructions in general domain are subreg accesses.
-        // Map them to NEON reg-reg moves.
-        if (Domain == ARMII::DomainGeneral)
-          Domain = ARMII::DomainNEON;
-      }
-    }
-
-    if ((Domain & ARMII::DomainNEON) && getSubtarget().hasNEON()) {
-      BuildMI(MBB, I, DL, get(ARM::VMOVQ), DestReg).addReg(SrcReg);
-    } else {
-      assert((Domain & ARMII::DomainVFP ||
-              !getSubtarget().hasNEON()) && "Invalid domain!");
-      AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::FCPYD), DestReg)
-                     .addReg(SrcReg));
-    }
+    AddDefaultPred(BuildMI(MBB, I, DL, get(ARM::FCPYD), DestReg)
+                   .addReg(SrcReg));
   } else if (DestRC == ARM::QPRRegisterClass ||
              DestRC == ARM::QPR_VFP2RegisterClass) {
     BuildMI(MBB, I, DL, get(ARM::VMOVQ), DestReg).addReg(SrcReg);

lib/Target/ARM/ARMTargetMachine.cpp

@@ -112,8 +112,11 @@ bool ARMBaseTargetMachine::addPreSched2(PassManagerBase &PM,
 bool ARMBaseTargetMachine::addPreEmitPass(PassManagerBase &PM,
                                           CodeGenOpt::Level OptLevel) {
   // FIXME: temporarily disabling load / store optimization pass for Thumb1.
-  if (OptLevel != CodeGenOpt::None && !Subtarget.isThumb1Only())
-    PM.add(createIfConverterPass());
+  if (OptLevel != CodeGenOpt::None) {
+    if (!Subtarget.isThumb1Only())
+      PM.add(createIfConverterPass());
+    PM.add(createNEONMoveFixPass());
+  }
 
   if (Subtarget.isThumb2()) {
     PM.add(createThumb2ITBlockPass());

lib/Target/ARM/NEONMoveFix.cpp

@@ -0,0 +1,144 @@
+//===-- NEONMoveFix.cpp - Convert vfp reg-reg moves into neon ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "neon-mov-fix"
+#include "ARM.h"
+#include "ARMMachineFunctionInfo.h"
+#include "ARMInstrInfo.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+STATISTIC(NumVMovs, "Number of reg-reg moves converted");
+
+namespace {
+  struct NEONMoveFixPass : public MachineFunctionPass {
+    static char ID;
+    NEONMoveFixPass() : MachineFunctionPass(&ID) {}
+
+    virtual bool runOnMachineFunction(MachineFunction &Fn);
+
+    virtual const char *getPassName() const {
+      return "NEON reg-reg move conversion";
+    }
+
+  private:
+    const TargetRegisterInfo *TRI;
+    const ARMBaseInstrInfo *TII;
+    const ARMSubtarget *Subtarget;
+
+    typedef DenseMap<unsigned, const MachineInstr*> RegMap;
+
+    bool InsertMoves(MachineBasicBlock &MBB);
+  };
+  char NEONMoveFixPass::ID = 0;
+}
+
+bool NEONMoveFixPass::InsertMoves(MachineBasicBlock &MBB) {
+  RegMap Defs;
+  bool Modified = false;
+
+  // Walk over MBB tracking the def points of the registers.
+  MachineBasicBlock::iterator MII = MBB.begin(), E = MBB.end();
+  MachineBasicBlock::iterator NextMII;
+  for (; MII != E; MII = NextMII) {
+    NextMII = next(MII);
+    MachineInstr *MI = &*MII;
+
+    if (MI->getOpcode() == ARM::FCPYD &&
+        !TII->isPredicated(MI)) {
+      unsigned SrcReg = MI->getOperand(1).getReg();
+      // If we do not found an instruction defining the reg, this means the
+      // register should be live-in for this BB. It's always to better to use
+      // NEON reg-reg moves.
+      unsigned Domain = ARMII::DomainNEON;
+      RegMap::iterator DefMI = Defs.find(SrcReg);
+      if (DefMI != Defs.end()) {
+        Domain = DefMI->second->getDesc().TSFlags & ARMII::DomainMask;
+        // Instructions in general domain are subreg accesses.
+        // Map them to NEON reg-reg moves.
+        if (Domain == ARMII::DomainGeneral)
+          Domain = ARMII::DomainNEON;
+      }
+
+      if ((Domain & ARMII::DomainNEON) && Subtarget->hasNEON()) {
+        // Convert FCPYD to VMOVD.
+        unsigned DestReg = MI->getOperand(0).getReg();
+
+        DEBUG({errs() << "vmov convert: "; MI->dump();});
+
+        // It's safe to ignore imp-defs / imp-uses here, since:
+        //  - We're running late, no intelligent condegen passes should be run
+        //    afterwards
+        //  - The imp-defs / imp-uses are superregs only, we don't care about
+        //    them.
+        BuildMI(MBB, *MI, MI->getDebugLoc(),
+                TII->get(ARM::VMOVD), DestReg).addReg(SrcReg);
+        MBB.erase(MI);
+        MachineBasicBlock::iterator I = prior(NextMII);
+        MI = &*I;
+
+        DEBUG({errs() << "        into: "; MI->dump();});
+
+        Modified = true;
+        ++NumVMovs;
+      } else {
+        assert((Domain & ARMII::DomainVFP ||
+                !Subtarget->hasNEON()) && "Invalid domain!");
+        // Do nothing.
+      }
+    }
+
+    // Update def information.
+    for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+      const MachineOperand& MO = MI->getOperand(i);
+      if (!MO.isReg() || !MO.isDef())
+        continue;
+      unsigned MOReg = MO.getReg();
+
+      Defs[MOReg] = MI;
+      // Catch subregs as well.
+      for (const unsigned *R = TRI->getSubRegisters(MOReg); *R; ++R)
+        Defs[*R] = MI;
+    }
+  }
+
+  return Modified;
+}
+
+bool NEONMoveFixPass::runOnMachineFunction(MachineFunction &Fn) {
+  ARMFunctionInfo *AFI = Fn.getInfo<ARMFunctionInfo>();
+  const TargetMachine &TM = Fn.getTarget();
+
+  if (AFI->isThumbFunction())
+    return false;
+
+  TRI = TM.getRegisterInfo();
+  Subtarget = &TM.getSubtarget<ARMSubtarget>();
+  TII = static_cast<const ARMBaseInstrInfo*>(TM.getInstrInfo());
+
+  bool Modified = false;
+  for (MachineFunction::iterator MFI = Fn.begin(), E = Fn.end(); MFI != E;
+       ++MFI) {
+    MachineBasicBlock &MBB = *MFI;
+    Modified |= InsertMoves(MBB);
+  }
+
+  return Modified;
+}
+
+/// createNEONMoveFixPass - Returns an instance of the NEON reg-reg moves fix
+/// pass.
+FunctionPass *llvm::createNEONMoveFixPass() {
+  return new NEONMoveFixPass();
+}