Changes from review:

- Move DisableScheduling flag into TargetOption.h
- Move SDNodeOrdering into its own header file. Give it a minimal interface that
  doesn't conflate construction with storage.
- Move assigning the ordering into the SelectionDAGBuilder.

This isn't used yet, so there should be no functional changes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91727 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetOptions.h

@@ -141,6 +141,11 @@ namespace llvm {
   /// wth earlier copy coalescing.
   extern bool StrongPHIElim;
 
+  /// DisableScheduling - This flag disables instruction scheduling. In
+  /// particular, it assigns an ordering to the SDNodes, which the scheduler
+  /// uses instead of its normal heuristics to perform scheduling.
+  extern bool DisableScheduling;
+
 } // End llvm namespace
 
 #endif