GNU Compiler Collection 4.3
The latest GCC 4.3 is set to take the programming world by storm with new optimizations, experimental support for the next-generation C++ 200x standard, an optional parallelized C++ STL, and a new Java compiler courtesy of the Eclipse project.
Following hot on the heels of GCC 4.2, the GNU Compiler Compilation  version 4.3 is now available . As could be expected, many functions tagged as obsolete have now been dropped, such as the -m386, -m486, -mpentium, and -mpentiumpro optimization options. If you really do need these legacy CPUs, you can reanimate them with the -march= and -mtune= options. Users with newer CPUs will appreciate dedicated optimization options for the AMD Geode and Intel Core 2, as well as the SSE3 (-msse3), SSE 4.1 (-msse4.1), and SSE 4.2 (-msse4.2) features.