[LLVMdev] LLVM 3.3 JIT code speed

[Stéphane Letz]

Le 19 juil. 2013 à 11:43, David Tweed <david.tweed at arm.com> a écrit :

> Hi,
> 
> | And since the 1) DSL  ==> C/C++  ===> clang/gcc -03 ===> exec  code chain
> has the "correct" speed, there is no reason the JIT based one should be
> slower right? 
> 
> | So I still guess something is wrong in the way we use the JIT and/or some
> LTO issue possibly?
> 
> When you say "slower" wrt 3.1 on LLVM and the same speed for clang, could
> you put some rough time numbers on things for some fixed testcode for your
> DSL? Obviously they won't have an absolute meaning, but the order of
> magnitude relative to the normal execution times might guide the ideas about
> what it could be.
> 
> Cheers,
> Dave
> 

About 20% slower with LLVM JIT 3.3 compared to clang 3.3, clang 3.1 and  LLVM JIT 3.1

Stéphane