In Thumb1, the register scavenger is not always able to use an emergency

[oota-llvm.git] / include / llvm / Target / TargetRegisterInfo.h

diff --git a/include/llvm/Target/TargetRegisterInfo.h b/include/llvm/Target/TargetRegisterInfo.h
index 6043ec8f61195d878b5cbfa474321ee015962177..11347b0e39296679d8f985ab850e6a2836d0c3a2 100644 (file)
--- a/include/llvm/Target/TargetRegisterInfo.h
+++ b/include/llvm/Target/TargetRegisterInfo.h
@@ -635,6 +635,24 @@ public:
   virtual void processFunctionBeforeFrameFinalized(MachineFunction &MF) const {
   }
 
+  /// saveScavengerRegister - Save the register so it can be used by the
+  /// register scavenger. Return true if the register was saved, false
+  /// otherwise. If this function does not save the register, the scavenger
+  /// will instead spill it to the emergency spill slot.
+  ///
+  virtual bool saveScavengerRegister(MachineBasicBlock &MBB,
+                                     MachineBasicBlock::iterator I,
+                                     const TargetRegisterClass *RC,
+                                     unsigned Reg) const {return false;}
+
+  /// restoreScavengerRegister - Restore a register saved by
+  /// saveScavengerRegister().
+  ///
+  virtual void restoreScavengerRegister(MachineBasicBlock &MBB,
+                                        MachineBasicBlock::iterator I,
+                                        const TargetRegisterClass *RC,
+                                        unsigned Reg) const {}
+
   /// eliminateFrameIndex - This method must be overriden to eliminate abstract
   /// frame indices from instructions which may use them.  The instruction
   /// referenced by the iterator contains an MO_FrameIndex operand which must be