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

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();
   

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<bool>
+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<MachineInstr*, unsigned> &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<MachineInstr*, unsigned>::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<MachineInstr*, unsigned> 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)

lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

@@ -69,10 +69,6 @@ EnableFastISelVerbose("fast-isel-verbose", cl::Hidden,
 static cl::opt<bool>
 EnableFastISelAbort("fast-isel-abort", cl::Hidden,
           cl::desc("Enable abort calls when \"fast\" instruction fails"));
-static cl::opt<bool>
-SchedLiveInCopies("schedule-livein-copies", cl::Hidden,
-                  cl::desc("Schedule copies of livein registers"),
-                  cl::init(false));
 
 #ifndef NDEBUG
 static cl::opt<bool>
@@ -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<MachineInstr*, unsigned> &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<MachineInstr*, unsigned>::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<MachineInstr*, unsigned> 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(),