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Allow a zero cycle stage to reserve/require a FU without advancing the cycle counter.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78736 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Goodwin
2009-08-11 22:38:43 +00:00
parent e28a2e8b70
commit 546952fd60
5 changed files with 75 additions and 44 deletions
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21
lib/CodeGen/ExactHazardRecognizer.cpp
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@ -39,7 +39,7 @@ ExactHazardRecognizer::ExactHazardRecognizer(const InstrItineraryData &LItinData
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 @@ ExactHazardRecognizer::HazardType ExactHazardRecognizer::getHazardType(SUnit *SU
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 @@ ExactHazardRecognizer::HazardType ExactHazardRecognizer::getHazardType(SUnit *SU
return Hazard;
}
++cycle;
if (IS->Cycles > 0)
++cycle;
}
}
@ -118,9 +123,13 @@ void ExactHazardRecognizer::EmitInstruction(SUnit *SU) {
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 @@ void ExactHazardRecognizer::EmitInstruction(SUnit *SU) {
assert(freeUnit && "No function unit available!");
Scoreboard[index] |= freeUnit;
++cycle;
if (IS->Cycles > 0)
++cycle;
}
}