DebugType = ParentDebugType;
#endif
- // Determine the maximum depth of any itinerary. This determines the
- // depth of the scoreboard. We always make the scoreboard at least 1
- // cycle deep to avoid dealing with the boundary condition.
+ // Determine the maximum depth of any itinerary. This determines the depth of
+ // the scoreboard. We always make the scoreboard at least 1 cycle deep to
+ // avoid dealing with the boundary condition.
unsigned ScoreboardDepth = 1;
if (ItinData && !ItinData->isEmpty()) {
IssueWidth = ItinData->IssueWidth;
// Find the next power-of-2 >= ItinDepth
while (ItinDepth > ScoreboardDepth) {
ScoreboardDepth *= 2;
+ // Don't set MaxLookAhead until we find at least one nonzero stage.
+ // This way, an itinerary with no stages has MaxLookAhead==0, which
+ // completely bypasses the scoreboard hazard logic.
+ MaxLookAhead = ScoreboardDepth;
}
}
- MaxLookAhead = ScoreboardDepth;
}
ReservedScoreboard.reset(ScoreboardDepth);
RequiredScoreboard.reset(ScoreboardDepth);
- DEBUG(dbgs() << "Using scoreboard hazard recognizer: Depth = "
- << ScoreboardDepth << '\n');
+ if (!MaxLookAhead)
+ DEBUG(dbgs() << "Disabled scoreboard hazard recognizer\n");
+ else
+ DEBUG(dbgs() << "Using scoreboard hazard recognizer: Depth = "
+ << ScoreboardDepth << '\n');
}
void ScoreboardHazardRecognizer::Reset() {