GCC 8.1 is a major release containing substantial new functionality not available in GCC 7.x or previous GCC releases.
This releases features significant improvements in the emitted diagnostics, including improved locations, location ranges and fix-it hints (especially in the C++ front-end), and various new warnings have been added.
Profile driven optimizations have been significantly improved, on x86 functions are now split into hot and cold regions by default. The link time optimizations now have a new way of emitting the DWARF debug information, which makes LTO optimized code more debuggable. New loop optimizers have added and existing improved and some, like -ftree-loop-distribution, -floop-unroll-and-jam and -floop-interchange have been enabled by default at-O3.
The AArch64 target now supports the Scalable Vector Extension, whichfeatures vectors with runtime determined number of elements.