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Adjust pushDeepSlotIfRequired (and rename to dupDeepSlotIfRequired).

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This commit is contained in:
Daniel Kirchner 2021-08-10 13:53:07 +02:00
parent eca4fb6781
commit 387c248601
1 changed files with 9 additions and 8 deletions
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17
libyul/backends/evm/StackHelpers.h
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@ -121,13 +121,14 @@ public:
private:
// If dupping an ideal slot causes a slot that will still be required to become unreachable, then dup
// the latter slot first.
static bool pushDeepSlotIfRequired(ShuffleOperations& _ops)
// @returns true, if it performed a dup.
static bool dupDeepSlotIfRequired(ShuffleOperations& _ops)
{
// Check if the stack is large enough for anything to potentially become unreachable.
if (_ops.sourceSize() < 15)
return false;
// Check whether any deep slot might still be needed later.
for (size_t sourceOffset: ranges::views::iota(0u, std::min(_ops.sourceSize() - 15, _ops.targetSize())))
for (size_t sourceOffset: ranges::views::iota(0u, _ops.sourceSize() - 15))
{
// We need another copy of this slot.
if (_ops.sourceMultiplicity(sourceOffset) > 0)
@ -151,9 +152,6 @@ private:
}
static void bringUpTargetSlot(ShuffleOperations& _ops, size_t _targetOffset)
{
if (pushDeepSlotIfRequired(_ops))
return;
std::list<size_t> toVisit{_targetOffset};
std::set<size_t> visited;
@ -193,7 +191,8 @@ private:
// Bring up all remaining target slots, if any, or terminate otherwise.
if (ops.sourceSize() < ops.targetSize())
{
bringUpTargetSlot(ops, ops.sourceSize());
if (!dupDeepSlotIfRequired(ops))
bringUpTargetSlot(ops, ops.sourceSize());
return true;
}
return false;
@ -237,7 +236,8 @@ private:
!ops.targetIsArbitrary(offset) // And that target slot is not arbitrary.
)
{
bringUpTargetSlot(ops, offset);
if (!dupDeepSlotIfRequired(ops))
bringUpTargetSlot(ops, offset);
return true;
}
@ -261,7 +261,8 @@ private:
// If we still need more slots, produce a suitable one.
if (ops.sourceSize() < ops.targetSize())
{
bringUpTargetSlot(ops, ops.sourceSize());
if (!dupDeepSlotIfRequired(ops))
bringUpTargetSlot(ops, ops.sourceSize());
return true;
}