Private versions had been floating for several years, but the development came to a halt for a while, because some licensing issues needed to be cleared.
The main advantage of GTC over TIGCC is that in addition to a cross-compiler running on computers, it has an on-calc compiler !
This compiler is stable and supports modern C syntax, unlike the much older 'cc'.
It handles fully or partially a number of extensions to the C standard known from GCC, and contains part of TIGCCLIB: in other words, many TIGCC programs can be compiled with GTC after no or few modifications. The opposite is true as well: GTC has C extensions of its own, so some GTC programs may require modifications to be compiled with TIGCC.
Read the installation procedure carefully: it requires a HW3Patch-type trick first.
One of the biggest drawbacks of GTC is that it doesn't currently have an IDE. However:
* since there's a proof of concept for integrating TIGCC in Code::Blocks (one of the portable, flexible, IDEs), and that it can compile the hundreds of source files of ExtGraph, it wouldn't be hard to do the same for GTC.
* of course, C::B and the others lack built-in support for the TIGCC Project infrastructure and IDE -> TIEmu transfers. But C::B and some others have a plug-in architecture, so it's likely feasible to add at least one of those two...
I'm not aware of any acceptable benchmark TIGCC vs. GTC . Someone had benchmarked three programs, with GTC showing good code generation... but that was way too small a sample for a fair benchmark.
A fair benchmark would involve at least a dozen of programs of various kinds (to be determined exactly).
Oh, yes, you want the link, perhaps ? Here it is: http://gtc.ti-fr.com/


