[fpc-devel] The 15k bounty: Optimizing executable speed for Linux x86 / LLVM

[Martin Schreiber]

On Saturday 27 October 2018 09:27:59 Sven Barth via fpc-devel wrote:
> >
> > Not really. The IR format has been pretty stable since version 3.9 or so
> > (LLVM is current at version 8.) As far as dependencies, it would add none
> > whatsoever other than a copy of the LLC or LLVM-AS binaries (as in, no
> > more than any other target FPC supports. Just think of it as yet another
> > assembler format.)
>
> It's more than just an additional assembler format as the infrastructure
> inside the compiler shows. Also there are the problems that Jonas
> mentioned.
> In my opinion that time is better spent optimizing our own code generator.
>
MSElang uses the approach to write LLVM bitcode directly without a temporary 
LLVM assembler text. Building the needed LLVM lists and tracking the ssa 
values is not trivial. IMO the worst aspect of LLVM is its slowness but the 
resulting code is awesome.

Martin