Add CopyCost to TargetRegisterClass. This specifies the cost of copying a value

between two registers in the specific class.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42123 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/Target/Target.td b/lib/Target/Target.td
index 4e495fb75c..15213ce283 100644
--- a/lib/Target/Target.td
+++ b/lib/Target/Target.td
@@ -104,6 +104,12 @@ class RegisterClass<string namespace, list<ValueType> regTypes, int alignment,
   //
   int Alignment = alignment;
 
+  // CopyCost - This value is used to specify the cost of copying a value
+  // between two registers in this register class. The default value is one
+  // meaning it takes a single instruction to perform the copying. A negative
+  // value means copying is extremely expensive or impossible.
+  int CopyCost = 1;
+
   // MemberList - Specify which registers are in this class.  If the
   // allocation_order_* method are not specified, this also defines the order of
   // allocation used by the register allocator.