discard cached cell values if the cell changes

FormulaGroupContext is actually a cache of cell results for OpenCL,
but the cached values are not always properly discarded. Happens e.g.
with testFormulaDepTracking in sc_ucalc fails if OpenCL is forced for
it (i.e. with mnOpenCLMinimumFormulaGroupSize disabled), because
a SetString() call for a cell doesn't invalidate the cache.

This obviously reduces the cache hit rate a bit, but according to my
tests it's not that bad (in fact the cache doesn't seem to get used
that often, so I even wonder if it's worth it).

Change-Id: Ia7ef2214956861d26ca3a42b84f9fecbff8316d0
Reviewed-on: https://gerrit.libreoffice.org/56087
Tested-by: Jenkins
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
(cherry picked from commit 954403938f00645d92520efc4433c440a133c0b9)
Reviewed-on: https://gerrit.libreoffice.org/56221
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

0 files changed, 0 insertions, 0 deletions