1 files changed, 46 insertions, 3 deletions

diff --git a/include/llvm/Target/TargetRegisterInfo.h b/include/llvm/Target/TargetRegisterInfo.h
index 121091c9b49b..205e76f9c6fc 100644
--- a/include/llvm/Target/TargetRegisterInfo.h
+++ b/include/llvm/Target/TargetRegisterInfo.h
@@ -46,6 +46,7 @@ struct TargetRegisterDesc {
   const unsigned *Overlaps;     // Overlapping registers, described above
   const unsigned *SubRegs;      // Sub-register set, described above
   const unsigned *SuperRegs;    // Super-register set, described above
+  unsigned CostPerUse;          // Extra cost of instructions using register.
 };
 
 class TargetRegisterClass {
@@ -426,6 +427,12 @@ public:
     return get(RegNo).Name;
   }
 
+  /// getCostPerUse - Return the additional cost of using this register instead
+  /// of other registers in its class.
+  unsigned getCostPerUse(unsigned RegNo) const {
+    return get(RegNo).CostPerUse;
+  }
+
   /// getNumRegs - Return the number of registers this target has (useful for
   /// sizing arrays holding per register information)
   unsigned getNumRegs() const {
@@ -588,11 +595,32 @@ public:
   }
 
   /// getCrossCopyRegClass - Returns a legal register class to copy a register
-  /// in the specified class to or from. Returns NULL if it is possible to copy
-  /// between a two registers of the specified class.
+  /// in the specified class to or from. If it is possible to copy the register
+  /// directly without using a cross register class copy, return the specified
+  /// RC. Returns NULL if it is not possible to copy between a two registers of
+  /// the specified class.
   virtual const TargetRegisterClass *
   getCrossCopyRegClass(const TargetRegisterClass *RC) const {
-    return NULL;
+    return RC;
+  }
+
+  /// getLargestLegalSuperClass - Returns the largest super class of RC that is
+  /// legal to use in the current sub-target and has the same spill size.
+  /// The returned register class can be used to create virtual registers which
+  /// means that all its registers can be copied and spilled.
+  virtual const TargetRegisterClass*
+  getLargestLegalSuperClass(const TargetRegisterClass *RC) const {
+    /// The default implementation is very conservative and doesn't allow the
+    /// register allocator to inflate register classes.
+    return RC;
+  }
+
+  /// getRegPressureLimit - Return the register pressure "high water mark" for
+  /// the specific register class. The scheduler is in high register pressure
+  /// mode (for the specific register class) if it goes over the limit.
+  virtual unsigned getRegPressureLimit(const TargetRegisterClass *RC,
+                                       MachineFunction &MF) const {
+    return 0;
   }
 
   /// getAllocationOrder - Returns the register allocation order for a specified
@@ -614,6 +642,14 @@ public:
     return 0;
   }
 
+  /// avoidWriteAfterWrite - Return true if the register allocator should avoid
+  /// writing a register from RC in two consecutive instructions.
+  /// This can avoid pipeline stalls on certain architectures.
+  /// It does cause increased register pressure, though.
+  virtual bool avoidWriteAfterWrite(const TargetRegisterClass *RC) const {
+    return false;
+  }
+
   /// UpdateRegAllocHint - A callback to allow target a chance to update
   /// register allocation hints when a register is "changed" (e.g. coalesced)
   /// to another register. e.g. On ARM, some virtual registers should target
@@ -631,6 +667,13 @@ public:
     return false;
   }
 
+  /// useFPForScavengingIndex - returns true if the target wants to use
+  /// frame pointer based accesses to spill to the scavenger emergency spill
+  /// slot.
+  virtual bool useFPForScavengingIndex(const MachineFunction &MF) const {
+    return true;
+  }
+
   /// requiresFrameIndexScavenging - returns true if the target requires post
   /// PEI scavenging of registers for materializing frame index constants.
   virtual bool requiresFrameIndexScavenging(const MachineFunction &MF) const {