diff options
Diffstat (limited to 'lib/CodeGen/ScheduleDAGInstrs.cpp')
| -rw-r--r-- | lib/CodeGen/ScheduleDAGInstrs.cpp | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/lib/CodeGen/ScheduleDAGInstrs.cpp b/lib/CodeGen/ScheduleDAGInstrs.cpp index 9c516c6edd..4ac2a3c5bf 100644 --- a/lib/CodeGen/ScheduleDAGInstrs.cpp +++ b/lib/CodeGen/ScheduleDAGInstrs.cpp @@ -699,10 +699,14 @@ void ScheduleDAGInstrs::initSUnits() { // Assign the Latency field of SU using target-provided information. SU->Latency = SchedModel.computeInstrLatency(SU->getInstr()); - // If this SUnit uses an unbuffered resource, mark it as such. - // These resources are used for in-order execution pipelines within an - // out-of-order core and are identified by BufferSize=1. BufferSize=0 is - // used for dispatch/issue groups and is not considered here. + // If this SUnit uses a reserved or unbuffered resource, mark it as such. + // + // Reserved resources block an instruction from issueing and stall the + // entire pipeline. These are identified by BufferSize=0. + // + // Unbuffered resources prevent execution of subsequeny instructions that + // require the same resources. This is used for in-order execution pipelines + // within an out-of-order core. These are identified by BufferSize=1. if (SchedModel.hasInstrSchedModel()) { const MCSchedClassDesc *SC = getSchedClass(SU); for (TargetSchedModel::ProcResIter |