- /// AdvanceCycle - This callback is invoked when no instructions can be
- /// issued on this cycle without a hazard. This should increment the
+ /// PreEmitNoops - This callback is invoked prior to emitting an instruction.
+ /// It should return the number of noops to emit prior to the provided
+ /// instruction.
+ /// Note: This is only used during PostRA scheduling. EmitNoop is not called
+ /// for these noops.
+ virtual unsigned PreEmitNoops(SUnit *) {
+ return 0;
+ }
+
+ /// ShouldPreferAnother - This callback may be invoked if getHazardType
+ /// returns NoHazard. If, even though there is no hazard, it would be better to
+ /// schedule another available instruction, this callback should return true.
+ virtual bool ShouldPreferAnother(SUnit *) {
+ return false;
+ }
+
+ /// AdvanceCycle - This callback is invoked whenever the next top-down
+ /// instruction to be scheduled cannot issue in the current cycle, either
+ /// because of latency or resource conflicts. This should increment the