On Fri, 2014-01-10 at 13:38 -0500, Adam Jensen wrote: > Is the mcode variant preferred over the gcc variant? What's the most > likely cause of ghdl-gcc failing tests while ghdl-mcode passes the > tests?
Generally no, neither is preferred; they serve different purposes and each has its strengths. One recent user found the gcc version choked with huge auto-generated VHDL source files (along the lines of gate-level netlists), consuming gigabytes of swap space during the (gcc backend) optimisation passes then falling over with allocation errors, while the mcode version sailed through the same test with 10% or less of the memory foootprint. Another user routinely links to C code (and I have linked to Ada) using the VHPI interface; as the mcode compiler supports neither of these languages, the gcc version is essential to him. > How significant is the run-time performance difference between the two? > (Personally, I am interested in the run-time performance of [large] > models with complex data structures - not just RTL and I especially > don't care about net-list simulation performance). Has anyone performed > any side-by-side characterizations of the two? I have performed precisely ONE such comparison and to my surprise, the penalty using the mcode compiler was only 20% (vs gcc at -O or -O1; at the time, -O2 and -O3 failed to compile; since fixed). More such comparisons could be useful. - Brian _______________________________________________ Ghdl-discuss mailing list [email protected] https://mail.gna.org/listinfo/ghdl-discuss
