[Info-vax] x86-64 VMS executable image sizes and memory requirements ?

[already5chosen at yahoo.com]

On Sunday, December 22, 2019 at 10:25:47 PM UTC+2, Michael Moroney wrote:
> already5chosen at yahoo.com writes:
> 
> >Few numbers for clang/LLVM on x86-64 (not VMS, of course)
> 
> >Option .text size
> >-O0 75456
> >-Oz 45772
> >-Os 44992
> >-O1 56836
> >-O2 45220
> >-O3 46084
> 
> For someone unfamiliar with clang & LLVM, what are the meanings of these
> optimization options?  And will they be available on VMS?

0 - no optimization
s - optimize for size, be reasonable
z - optimize for size, even at cost of slowdown
1 - optimize for speed, but don't go out of your ways
2 - optimize for speed, default
3 - optimize for speed, gamble. In practice, on clang/LLVM it is similar to 2

As you can see, in my case -Oz does not do what it is intended to do. Shit happens. After all, according to my understanding, compiler does not work like, for example, chess engine. It does not try several possibilities select the best. Instead, it relies of heuristics.