- First compare the d-pointer before dipping into *d
- Keep a running count as we calculate thisEqualRange, as
std::distance() on QHash::iterator is very expensive.
- Skip the pointless first comparison of the unadvanced
iterator's key() with itself (found by Mårten Nordheim)
Also rename (it, thisEqualRangeEnd) → (thisEqualRangeStart, it),
to keep advancing `it`, which is more natural than advancing
an `end` and later resetting it = end.
Change-Id: I2c27c071b9ee23425a763328402dad9efee4cbd0
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
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