Bad performance (with GCC 11.3.0 - O3) of a small etude in C

Bad performance (with GCC 11.3.0 - O3) of a small etude in C

[Georgi Marinov]

Hi,
just wanted to let you know that I found that GCC 11.3.0 -O3 is generating code with many unnecessary jumps (while CLANG 14.0.1 -O3 not) in a small partitioning (for Quicksort) 15 lines of code etude.
In case you are interested I will submit the three disassembly outputs, plus ICL 19.0 -O3, ICL is horrible in that, ICL 15.0 was good but they ruined their legacy.
Generally, GCC is my target compiler, yet, CLANG is better in my usecases. I would like some of your coders to look it up, my wish is GCC to catch up.

Regards

Re: Bad performance (with GCC 11.3.0 - O3) of a small etude in C

[Martin Liška]

On 7/8/22 06:31, Georgi Marinov via Gcc wrote:
> Hi,
> just wanted to let you know that I found that GCC 11.3.0 -O3 is generating code with many unnecessary jumps (while CLANG 14.0.1 -O3 not) in a small partitioning (for Quicksort) 15 lines of code etude.
> In case you are interested I will submit the three disassembly outputs, plus ICL 19.0 -O3, ICL is horrible in that, ICL 15.0 was good but they ruined their legacy.
> Generally, GCC is my target compiler, yet, CLANG is better in my usecases. I would like some of your coders to look it up, my wish is GCC to catch up.
> 
> Regards

Hi.

Please file a bug here:
https://gcc.gnu.org/bugzilla/

with a reproducer we can take a look.

Thanks,
Martin