getCommonSubClass() - Calculate the largest common sub-class of two register

classes.

This is implemented as a function rather than a method on TargetRegisterClass
because it is symmetric in its arguments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70512 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 0 deletions

diff --git a/include/llvm/Target/TargetRegisterInfo.h b/include/llvm/Target/TargetRegisterInfo.h
index 16cec2d647..fbb8ffe812 100644
--- a/include/llvm/Target/TargetRegisterInfo.h
+++ b/include/llvm/Target/TargetRegisterInfo.h
@@ -254,6 +254,10 @@ public:
   int getCopyCost() const { return CopyCost; }
 };
 
+/// getCommonSubClass - find the largest common subclass of A and B. Return NULL
+/// if there is no common subclass.
+const TargetRegisterClass *getCommonSubClass(const TargetRegisterClass *A,
+                                             const TargetRegisterClass *B);
 
 /// TargetRegisterInfo base class - We assume that the target defines a static
 /// array of TargetRegisterDesc objects that represent all of the machine