> ... gcc 5 changes ...

I'm disappointed it says literally nothing about auto-vectorization. I had to do an incredible amount of hand-holding to get GFortran 4.9's auto-vectorization to work worth anything. A few experiments with C code showed that GCC 4.9 was just plain bad at it compared to even Clang, much less ICC. If I work on that project again, I'll probably look into getting DragonEgg [1] to work so I can get decent optimization without contorting the code as much.

The OP mentions an important case with loads and stores of 3D data, but GCC needs to up its game in more ways than that.

[1] http://dragonegg.llvm.org/

Actually Clang doesn't implement the listed built-in functions (yet?). They're type-generic versions.

http://llvm.org/releases/3.5.0/tools/clang/docs/LanguageExte...

http://clang.llvm.org/docs/LanguageExtensions.html#checked-a...

Ah yes. The generic versions are nicer to use, and can be used for mixed types. It seems gcc will implement the clang compatible ones too.

I'm guessing from the libstdc++ change log that GCC 5.x will instigate an ABI break?