- Added regsOverlap() to test if two registers overlap. Or in case they are

virtual registers, test if they the same.
- Added a virtual method to return target specific reserved registers, e.g. SP.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34375 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/MRegisterInfo.h

@@ -284,6 +284,17 @@ public:
     return false;
   }
 
+  /// regsOverlap - Returns true if the two registers are equal or alias
+  /// each other. The registers may be virtual register.
+  bool regsOverlap(unsigned regA, unsigned regB) const {
+    if (regA == regB)
+      return true;
+
+    if (isVirtualRegister(regA) || isVirtualRegister(regB))
+      return false;
+    return areAliases(regA, regB);
+  }
+
   /// getCalleeSavedRegs - Return a null-terminated list of all of the
   /// callee saved registers on this target. The register should be in the
   /// order of desired callee-save stack frame offset. The first register is
@@ -295,6 +306,12 @@ public:
   /// length of this list match the getCalleeSaveRegs() list.
   virtual const TargetRegisterClass* const *getCalleeSavedRegClasses() const =0;
 
+  /// getReservedRegs - Returns a bitset indexed by physical register number
+  /// indicating if a register is a special register that has particular uses and
+  /// should be considered unavailable at all times, e.g. SP, RA. This is used by
+  /// register scavenger to determine what registers are free.
+  virtual BitVector getReservedRegs(const MachineFunction &MF) const = 0;
+
   //===--------------------------------------------------------------------===//
   // Register Class Information
   //