GCC4 on Alpha3

Hi there.

Can I get GCC4 in official release Alpha3 ?

Haiku R1 Alpha 3 is a “gcc2 hybrid” version, which mean that the default compiler and ABI (so libraries) are gcc2 one.
So, if you mean the gcc4 compiler, yes, it’s already there, but it’s not the one active by default.
To switch to gcc4 instead of gcc2 compiler, simply type this in a Terminal:

setgcc gcc4

If you mean having an Haiku alpha3 version but build only with and for gcc4 ABI, the answer is nope, as per design and backward beos binary compatibility, all official R1* releases are gcc2 hybrid build.
But you can easily donwload a gcc4 only or gcc4 hybrid nightly Haiku build, latest or the revision right after R1A3 was released.