memset and related things

[Walter Bright]

Don wrote:
> I presume you're talking about integer optimisation, because that's 
> definitely not the case for DMD's floating point. Eg, there's a comment 
> in the code somewhere saying that CSE (complex sub expression) 
> optimisations are not done for floating point because the code generator 
> can't cope with it. It does loops particularly poorly, it never seems to 
> keep a variable on the FP stack, so it keeps loading an saving them. The 
> potential speedups are enormous.


I'll agree with you on that assessment.