The ltl_to_tgba_fm() translation function was using a hash_map of
maps (ugh!) to merge transitions on output. However recent libstd++
changed the implementation of hash_map (a.k.a. unordered_map) causing
transitions to be output in a different order. This
implementation-dependent order caused the ltl2ta.test to fail because
the BA->TA transformation can produce TA of different sizes if you
simply change the order of transitions in the input BA! This does not
sound like a nice property for the BA->TA transformation, but Ala Eddine
isn't sure how to fix it yet. In the meantime, this patch makes sure
ltl_to_tgba_fm() will return the same output regardless of the
implementation of hash_map.
The ltl2ta.test failure has been observed with g++ 4.9.2 on Arch Linux,
and with gcc-snapshot (5.0.0 20141016) on Debian.
* src/tgbaalgos/ltl2tgba_fm.cc: Rewrite the transition merging
using a std::vector and std::sort instead of nested maps tables.
* src/tgbatest/ltl2ta.test: Adjust sizes to the new order.
* NEWS: Mention the fix.
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