diff options
Diffstat (limited to 'llvm/lib/CodeGen/MachineScheduler.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/MachineScheduler.cpp | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/MachineScheduler.cpp b/llvm/lib/CodeGen/MachineScheduler.cpp index 0858be6..03e892a5 100644 --- a/llvm/lib/CodeGen/MachineScheduler.cpp +++ b/llvm/lib/CodeGen/MachineScheduler.cpp @@ -3777,6 +3777,21 @@ SUnit *GenericScheduler::pickNode(bool &IsTopNode) { } } while (SU->isScheduled); + // If IsTopNode, then SU is in Top.Available and must be removed. Otherwise, + // if isTopReady(), then SU is in either Top.Available or Top.Pending. + // If !IsTopNode, then SU is in Bot.Available and must be removed. Otherwise, + // if isBottomReady(), then SU is in either Bot.Available or Bot.Pending. + // + // It is coincidental when !IsTopNode && isTopReady or when IsTopNode && + // isBottomReady. That is, it didn't factor into the decision to choose SU + // because it isTopReady or isBottomReady, respectively. In fact, if the + // RegionPolicy is OnlyTopDown or OnlyBottomUp, then the Bot queues and Top + // queues respectivley contain the original roots and don't get updated when + // picking a node. So if SU isTopReady on a OnlyBottomUp pick, then it was + // because we schduled everything but the top roots. Conversley, if SU + // isBottomReady on OnlyTopDown, then it was because we scheduled everything + // but the bottom roots. If its in a queue even coincidentally, it should be + // removed so it does not get re-picked in a subsequent pickNode call. if (SU->isTopReady()) Top.removeReady(SU); if (SU->isBottomReady()) |