Re: Abt SIMD Emulation

[Paolo Bonzini <paolo dot bonzini at lu dot unisi dot ch>]

> > For targets which doesn't have simd hardware support like fr30 ,  simd stuff is emulated?
> > Is there some flags/macros in gcc to indicate that?
>
> To indicate what?

I guess to indicate that the vector is emulated.  The TYPE_MODE of the 
vector type, in that case, is BLKmode or an integer mode.

> > How is it done in other targets which deosnt have the hardware support?
>
> In the obvious tedious way: as a loop over the elements.

With the additional optimization that & | ^ ~ can be done word-by-word, 
+ - can use bit-twiddling if there are at least 4 elements by word 
(otherwise it is not profitable), and that smaller SIMD instructions 
(e.g. 2 8-byte SIMD instructions to emulate a 16-byte vector) may be 
used if supported.

See tree-ssa-vect-generic.c for the gory details.

Paolo