Allow a zero cycle stage to reserve/require a FU without advancing the cycle counter.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78736 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ExactHazardRecognizer.cpp b/lib/CodeGen/ExactHazardRecognizer.cpp
index 5a89d22..48043f2 100644
--- a/lib/CodeGen/ExactHazardRecognizer.cpp
+++ b/lib/CodeGen/ExactHazardRecognizer.cpp
@@ -39,7 +39,7 @@
unsigned ItinDepth = 0;
for (; IS != E; ++IS)
- ItinDepth += IS->Cycles;
+ ItinDepth += std::max(1U, IS->Cycles);
ScoreboardDepth = std::max(ScoreboardDepth, ItinDepth);
}
@@ -89,9 +89,13 @@
unsigned idx = SU->getInstr()->getDesc().getSchedClass();
for (const InstrStage *IS = ItinData.begin(idx), *E = ItinData.end(idx);
IS != E; ++IS) {
+ // If the stages cycles are 0, then we must have the FU free in
+ // the current cycle, but we don't advance the cycle time .
+ unsigned StageCycles = std::max(1U, IS->Cycles);
+
// We must find one of the stage's units free for every cycle the
// stage is occupied.
- for (unsigned int i = 0; i < IS->Cycles; ++i) {
+ for (unsigned int i = 0; i < StageCycles; ++i) {
assert((cycle < ScoreboardDepth) && "Scoreboard depth exceeded!");
unsigned index = getFutureIndex(cycle);
@@ -103,7 +107,8 @@
return Hazard;
}
- ++cycle;
+ if (IS->Cycles > 0)
+ ++cycle;
}
}
@@ -118,9 +123,13 @@
unsigned idx = SU->getInstr()->getDesc().getSchedClass();
for (const InstrStage *IS = ItinData.begin(idx), *E = ItinData.end(idx);
IS != E; ++IS) {
+ // If the stages cycles are 0, then we must reserve the FU in the
+ // current cycle, but we don't advance the cycle time .
+ unsigned StageCycles = std::max(1U, IS->Cycles);
+
// We must reserve one of the stage's units for every cycle the
// stage is occupied.
- for (unsigned int i = 0; i < IS->Cycles; ++i) {
+ for (unsigned int i = 0; i < StageCycles; ++i) {
assert((cycle < ScoreboardDepth) && "Scoreboard depth exceeded!");
unsigned index = getFutureIndex(cycle);
@@ -135,7 +144,9 @@
assert(freeUnit && "No function unit available!");
Scoreboard[index] |= freeUnit;
- ++cycle;
+
+ if (IS->Cycles > 0)
+ ++cycle;
}
}