std::pow implementation

[Gabriel Dos Reis]

Richard Guenther <rguenth@tat.physik.uni-tuebingen.de> writes:

[...]

| > No, always_inline also implies inlining functions that call alloca, so
| > it's a bit stronger than that.
| >
| > The attached patch makes C++ ignore inline limits if the function was
| > declared with "inline".  Maybe you can try and see what it does for you?
| 
| It does no good, as it is certainly worse than #define inline
| __attribute__((always_inline)) and that made compile times and code size
| go through the roof last time I checked, but read on ...

Without decent constant propagation and dead code elimination, it does
not suffice -- as you have seen it in a PR your reported.

-- Gaby