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[Hexagon] Check weak dependences when only 1 instruction is available 

Patch by Brendon Cahoon.

llvm-svn: 327997
This commit is contained in:
Krzysztof Parzyszek 2018-03-20 16:22:06 +00:00
parent 9af71b3875
commit 73be83dec5
1 changed files with 13 additions and 9 deletions
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22
llvm/lib/Target/Hexagon/HexagonMachineScheduler.cpp
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@ -466,6 +466,10 @@ void ConvergingVLIWScheduler::VLIWSchedBoundary::removeReady(SUnit *SU) {
}
}
static unsigned getWeakLeft(const SUnit *SU, bool IsTop) {
return (IsTop) ? SU->WeakPredsLeft : SU->WeakSuccsLeft;
}
/// If this queue only has one ready candidate, return it. As a side effect,
/// advance the cycle until at least one node is ready. If multiple instructions
/// are ready, return NULL.
@ -473,11 +477,15 @@ SUnit *ConvergingVLIWScheduler::VLIWSchedBoundary::pickOnlyChoice() {
if (CheckPending)
releasePending();
for (unsigned i = 0;
Available.empty() ||
(Available.size() == 1 &&
!ResourceModel->isResourceAvailable(*Available.begin(), isTop()));
++i) {
auto AdvanceCycle = [this]() {
if (Available.empty())
return true;
if (Available.size() == 1 && Pending.size() > 0)
return !ResourceModel->isResourceAvailable(*Available.begin(), isTop()) ||
getWeakLeft(*Available.begin(), isTop()) != 0;
return false;
};
for (unsigned i = 0; AdvanceCycle(); ++i) {
assert(i <= (HazardRec->getMaxLookAhead() + MaxMinLatency) &&
"permanent hazard"); (void)i;
ResourceModel->reserveResources(nullptr, isTop());
@ -629,10 +637,6 @@ int ConvergingVLIWScheduler::pressureChange(const SUnit *SU, bool isBotUp) {
return 0;
}
static unsigned getWeakLeft(const SUnit *SU, bool IsTop) {
return (IsTop) ? SU->WeakPredsLeft : SU->WeakSuccsLeft;
}
// Constants used to denote relative importance of
// heuristic components for cost computation.
static const unsigned PriorityOne = 200;