Initial hazard recognizer support in post-pass scheduling. This includes

a new toy hazard recognizier heuristic which attempts to direct the
scheduler to avoid clumping large groups of loads or stores too densely.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62291 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/ScheduleHazardRecognizer.h

@@ -55,7 +55,10 @@ public:
 
   /// EmitNoop - This callback is invoked when a noop was added to the
   /// instruction stream.
-  virtual void EmitNoop() {}
+  virtual void EmitNoop() {
+    // Default implementation: count it as a cycle.
+    AdvanceCycle();
+  }
 };
 
 }