Move CalculateRegClass to MRI::recomputeRegClass.

This function doesn't have anything to do with spill weights, and MRI
already has functions for manipulating the register class of a virtual
register.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137123 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h
index 6fd983ba50..5eeaa28747 100644
--- a/include/llvm/CodeGen/MachineRegisterInfo.h
+++ b/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -219,9 +219,20 @@ public:
   /// Return the new register class, or NULL if no such class exists.
   /// This should only be used when the constraint is known to be trivial, like
   /// GR32 -> GR32_NOSP. Beware of increasing register pressure.
+  ///
   const TargetRegisterClass *constrainRegClass(unsigned Reg,
                                                const TargetRegisterClass *RC);
 
+  /// recomputeRegClass - Try to find a legal super-class of Reg's register
+  /// class that still satisfies the constraints from the instructions using
+  /// Reg.  Returns true if Reg was upgraded.
+  ///
+  /// This method can be used after constraints have been removed from a
+  /// virtual register, for example after removing instructions or splitting
+  /// the live range.
+  ///
+  bool recomputeRegClass(unsigned Reg, const TargetMachine&);
+
   /// createVirtualRegister - Create and return a new virtual register in the
   /// function with the specified register class.
   ///