Teach the inline spiller to attempt folding a load instruction into its single

[oota-llvm.git] / lib / CodeGen / MachineRegisterInfo.cpp

diff --git a/lib/CodeGen/MachineRegisterInfo.cpp b/lib/CodeGen/MachineRegisterInfo.cpp
index 3982499eab6b0a477c022e2dd5863ad86f2f41d9..7b839f07e73c6a0b813158f4f2fd2738fe835592 100644 (file)
--- a/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/lib/CodeGen/MachineRegisterInfo.cpp
@@ -37,6 +37,7 @@ MachineRegisterInfo::~MachineRegisterInfo() {
            "PhysRegUseDefLists has entries after all instructions are deleted");
 #endif
   delete [] PhysRegUseDefLists;
+  delete [] RegClass2VRegMap;
 }
 
 /// setRegClass - Set the register class of the specified virtual register.
@@ -59,6 +60,20 @@ MachineRegisterInfo::setRegClass(unsigned Reg, const TargetRegisterClass *RC) {
   RegClass2VRegMap[RC->getID()].push_back(VR);
 }
 
+const TargetRegisterClass *
+MachineRegisterInfo::constrainRegClass(unsigned Reg,
+                                       const TargetRegisterClass *RC) {
+  const TargetRegisterClass *OldRC = getRegClass(Reg);
+  if (OldRC == RC)
+    return RC;
+  const TargetRegisterClass *NewRC = getCommonSubClass(OldRC, RC);
+  if (!NewRC)
+    return 0;
+  if (NewRC != OldRC)
+    setRegClass(Reg, NewRC);
+  return NewRC;
+}
+
 /// createVirtualRegister - Create and return a new virtual register in the
 /// function with the specified register class.
 ///
@@ -181,21 +196,29 @@ MachineRegisterInfo::EmitLiveInCopies(MachineBasicBlock *EntryMBB,
                                       const TargetRegisterInfo &TRI,
                                       const TargetInstrInfo &TII) {
   // 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,
-                                      DebugLoc());
-      assert(Emitted && "Unable to issue a live-in copy instruction!\n");
-      (void) Emitted;
+  for (unsigned i = 0, e = LiveIns.size(); i != e; ++i)
+    if (LiveIns[i].second) {
+      if (use_empty(LiveIns[i].second)) {
+        // The livein has no uses. Drop it.
+        //
+        // It would be preferable to have isel avoid creating live-in
+        // records for unused arguments in the first place, but it's
+        // complicated by the debug info code for arguments.
+        LiveIns.erase(LiveIns.begin() + i);
+        --i; --e;
+      } else {
+        // Emit a copy.
+        BuildMI(*EntryMBB, EntryMBB->begin(), DebugLoc(),
+                TII.get(TargetOpcode::COPY), LiveIns[i].second)
+          .addReg(LiveIns[i].first);
+
+        // Add the register to the entry block live-in set.
+        EntryMBB->addLiveIn(LiveIns[i].first);
+      }
+    } else {
+      // Add the register to the entry block live-in set.
+      EntryMBB->addLiveIn(LiveIns[i].first);
     }
-
-  // Add function live-ins to entry block live-in set.
-  for (MachineRegisterInfo::livein_iterator I = livein_begin(),
-         E = livein_end(); I != E; ++I)
-    EntryMBB->addLiveIn(I->first);
 }
 
 void MachineRegisterInfo::closePhysRegsUsed(const TargetRegisterInfo &TRI) {