Add callback to allow target to adjust latency of schedule dependency edge.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78910 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/ScheduleDAG.h

@@ -145,6 +145,11 @@ namespace llvm {
       return Latency;
     }
 
+    /// setLatency - Set the latency for this edge.
+    void setLatency(unsigned Lat) {
+      Latency = Lat;
+    }
+
     //// getSUnit - Return the SUnit to which this edge points.
     SUnit *getSUnit() const {
       return Dep.getPointer();

include/llvm/Target/TargetSubtarget.h

@@ -16,6 +16,8 @@
 
 namespace llvm {
 
+class SDep;
+
 //===----------------------------------------------------------------------===//
 ///
 /// TargetSubtarget - Generic base class for all target subtargets.  All
@@ -35,6 +37,10 @@ public:
   /// indicating the number of scheduling cycles of backscheduling that
   /// should be attempted.
   virtual unsigned getSpecialAddressLatency() const { return 0; }
+
+  // adjustSchedDependency - Perform target specific adjustments to
+  // the latency of a schedule dependency.
+  virtual void adjustSchedDependency(SDep&) const { };
 };
 
 } // End llvm namespace