Add TargetRegisterInfo::getRawAllocationOrder().

This virtual function will replace allocation_order_begin/end as the one
to override when implementing custom allocation orders. It is simpler to
have one function return an ArrayRef than having two virtual functions
computing different ends of the same array.

Use getRawAllocationOrder() in place of allocation_order_begin() where
it makes sense, but leave some clients that look like they really want
the filtered allocation orders from RegisterClassInfo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133170 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 22 insertions, 0 deletions

diff --git a/include/llvm/Target/TargetRegisterInfo.h b/include/llvm/Target/TargetRegisterInfo.h
index dc2d07aa4d..7a9573041c 100644
--- a/include/llvm/Target/TargetRegisterInfo.h
+++ b/include/llvm/Target/TargetRegisterInfo.h
@@ -18,6 +18,7 @@
 
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/ValueTypes.h"
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseSet.h"
 #include <cassert>
 #include <functional>
@@ -259,6 +260,27 @@ public:
     return end();
   }
 
+  /// getRawAllocationOrder - Returns the preferred order for allocating
+  /// registers from this register class in MF. The raw order comes directly
+  /// from the .td file and may include reserved registers that are not
+  /// allocatable. Register allocators should also make sure to allocate
+  /// callee-saved registers only after all the volatiles are used. The
+  /// RegisterClassInfo class provides filtered allocation orders with
+  /// callee-saved registers moved to the end.
+  ///
+  /// The MachineFunction argument can be used to tune the allocatable
+  /// registers based on the characteristics of the function, subtarget, or
+  /// other criteria.
+  ///
+  /// By default, this method returns all registers in the class.
+  ///
+  virtual
+  ArrayRef<unsigned> getRawAllocationOrder(const MachineFunction &MF) const {
+    iterator B = allocation_order_begin(MF);
+    iterator E = allocation_order_end(MF);
+    return ArrayRef<unsigned>(B, E - B);
+  }
+
   /// getSize - Return the size of the register in bytes, which is also the size
   /// of a stack slot allocated to hold a spilled copy of this register.
   unsigned getSize() const { return RegSize; }