diff options
| -rw-r--r-- | llvm/include/llvm/CodeGen/ScheduleDAG.h | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/llvm/include/llvm/CodeGen/ScheduleDAG.h b/llvm/include/llvm/CodeGen/ScheduleDAG.h index d80bdf8e281..8c959da696d 100644 --- a/llvm/include/llvm/CodeGen/ScheduleDAG.h +++ b/llvm/include/llvm/CodeGen/ScheduleDAG.h @@ -52,11 +52,21 @@ namespace llvm { Order ///< Any other ordering dependency. }; + // Strong dependencies must be respected by the scheduler. Artificial + // dependencies may be removed only if they are redundant with another + // strong depedence. + // + // Weak dependencies may be violated by the scheduling strategy, but only if + // the strategy can prove it is correct to do so. + // + // Strong OrderKinds must occur before "Weak". + // Weak OrderKinds must occur after "Weak". enum OrderKind { Barrier, ///< An unknown scheduling barrier. MayAliasMem, ///< Nonvolatile load/Store instructions that may alias. MustAliasMem, ///< Nonvolatile load/Store instructions that must alias. - Artificial, ///< Arbitrary weak DAG edge (no actual dependence). + Artificial, ///< Arbitrary strong DAG edge (no real dependence). + Weak, ///< Arbitrary weak DAG edge. Cluster ///< Weak DAG edge linking a chain of clustered instrs. }; @@ -205,7 +215,7 @@ namespace llvm { /// not force ordering. Breaking a weak edge may require the scheduler to /// compensate, for example by inserting a copy. bool isWeak() const { - return getKind() == Order && Contents.OrdKind == Cluster; + return getKind() == Order && Contents.OrdKind >= Weak; } /// isArtificial - Test if this is an Order dependence that is marked |
