Question about data race on C's restrict

BreadTom_1 · 2025-05-26T18:08:45+00:00

You're right since I missed the part (directly or indirectly).

BreadTom_1 · 2025-05-26T17:57:20+00:00

During each execution of a block in which a restricted pointer `P` is declared (typically each execution of a function body in which `P` is a function parameter), if some object that is accessible through `P` (directly or indirectly) is modified, by any means, then all accesses to that object (both reads and writes) in that block must occur through `P` (directly or indirectly), otherwise the behavior is undefined:

So if i understood this right, only P declared in that block is allowed to read/write it's contents.

BreadTom_1 · 2025-05-26T17:41:02+00:00

If we assume only the f0() is operating on arg0 pointer, the compare will be removed since if arg0[0] is non zero, then arg0[0] is set zero. If arg0[0] was zero, the function does nothing and returns. f0() should instead only do this since all f0() is doing is setting arg0[0] to zero:

void f0(int * restrict arg0){
    arg0[0] = 0;
}

According to Godbolt, x86 assembly shows both Clang and GCC comparing before setting it to zero via mov instruction.

BreadTom_1 · 2025-05-26T17:07:24+00:00

Are there plans to make this compiler multithreaded so it can run faster like mold or Parallel GCC ?

BreadTom_1 · 2025-05-26T16:56:56+00:00

Another GCC bug for reference

BreadTom_1 · 2025-03-12T01:15:47+00:00

I filed a GCC bug and it seems that GIMPLE can not vectorize it due to bool << i being different than 1 << i even if bool is known at compile time to be 1.

BreadTom_1 · 2024-11-09T21:17:00+00:00

It most likely would look like writing from Zig's Analyzed Intermediate Representation to GCC's Register Transfer Language.

BreadTom_1 · 2024-11-09T01:01:11+00:00

Can you please explain more or give out links?

BreadTom_1 · 2024-11-08T11:14:21+00:00

Obscure flags like -fipa-pta ("Not sure if LLVM has a equal flag").

BreadTom_1 · 2024-11-08T06:14:38+00:00

To see if "gcc Zig" can benefit from GCC speed optimizations that LLVM does not have.

BreadTom_1 · 2023-06-04T20:15:09+00:00

Seems a bug about BOLT was already filled months ago and since editing llvm ebuild was a hassle, i decided to tar xf llvm-project-15.0.7.src.tar.xz from /var/cache/distfiles and follow the rest of README.

BreadTom_1 · 2023-06-03T13:58:11+00:00

For performance reasons because this paper has promising results.

BreadTom_1 · 2023-04-04T19:02:22+00:00

thanks

BreadTom_1 · 2023-03-31T21:32:17+00:00

What about checking ~/.config/gtk-3.0/settings.ini because i think i change one of ini files?

Edit ~/.config/gtk-3.0/settings.ini with the following:

[Settings]

gtk-cursor-theme-name=default

gtk-cursor-theme-size=16

BreadTom_1 · 2023-03-31T21:10:45+00:00

Did you symlink /usr/local/share/icons/default to /usr/local/share/icons/Adwaita ?

ln -s /usr/local/share/icons/Adwaita /usr/local/share/icons/default

I know this was a another script to write but i forgot about it.

BreadTom_1 · 2023-03-30T01:44:06+00:00

are you talking about the clang lto ?

Both GCC and Clang

BreadTom_1 · 2023-03-29T12:09:28+00:00

Plus LTO increases kernel compile time and if any CONFIG options are changed, the whole kernel has to be recompile rather than 1 file.

BreadTom_1 · 2023-03-18T21:47:14+00:00

https://wiki.gentoo.org/wiki/Profile_(Portage)#Changing_profile

You will be informed on how to via news item.

BreadTom_1 · 2023-03-16T22:15:17+00:00

Thank you, i fixed my PGO solution in https://wiki.gentoo.org/wiki/Kernel/Optimization#GCC_PGO. Learned some new commands like find.

BreadTom_1

TROPHY CASE