This essentially adds wide port support for free in passes that don't
have a usefully better way of handling wide ports than just breaking
them up to narrow ports, avoiding "please run memory_narrow" annoyance.
There will soon be more (versioned) memory cells, so handle passes that
only care if a cell is memory-related by a simple helper call instead of
a hardcoded list.
Refer to the SMT-LIB specification, section 4.1.7. According to the spec, some options can only be specified in `start` mode. Once the solver sees `set-logic`, it moves to `assert` mode.
The $div and $mod cells use truncating division semantics (rounding
towards 0), as defined by e.g. Verilog. Another rounding mode, flooring
(rounding towards negative infinity), can be used in e.g. VHDL. The
new $modfloor cell provides this flooring modulo (also known as "remainder"
in several languages, but this name is ambiguous).
This commit also fixes the handling of $mod in opt_expr, which was
previously optimized as if it was $modfloor.
Ensures that "BV" is the logic whenever solving an exists-forall problem with Yices, moves the "(set-logic ...)" directive above any non-info line, sets the `ef-max-iters` parameter to a very high number when using Yices in exists-forall mode so as not to prematurely abandon difficult problems, and does not provide the incompatible "--incremental" Yices argument when in exists-forall mode.
Modifies smt2 backend to recognize `$anyconst` etc. assigned to a wire with the `maximize` or `minimize` attribute and emit `; yosys-smt2-maximize` or `; yosys-smt2-minimize` directives as appropriate.
Modifies `backends/smt2/smtbmc.py` and `smtio.py` to recognize those directives and emit a `(maximize ...)` or `(minimize ...)` command at the end of `smt_forall_assert()`, as described in the paper "νZ - An Optimizing SMT Solver" by Nikolaj Bjørner et al.
Adds an example `examples/smtbmc/demo9.v` to show how it can be used.
The Makefile assumes the compiler is called `gcc`, which isn't always
true. In fact, if we're building on msys2 or msys2-64, the compiler
is called `i686-w64-mingw32-g++` or `x86_64-w64-mingw32-g++`.
Use the variable instead of hardcoding the name, to fix building on
these systems.
Signed-off-by: Sean Cross <sean@xobs.io>