Notices by Max (goldstein@im-in.space)

Embed this notice
Max (goldstein@im-in.space)'s status on Sunday, 10-Nov-2024 06:54:27 JST Max

MSVC is the only compiler to apply optimizations based on restrict on local variables, which it immediately remediates by generating a lot more stack shuffling than GCC or Clang: https://godbolt.org/z/954dGcabx
In conversation about 17 days ago from im-in.space permalink
Attachments
1. Domain not in remote thumbnail source whitelist: raw.githubusercontent.com
  
  Compiler Explorer - C
  
  from Matt Godbolt
  
  void black_box(int); int* gimme_a_pointer(void); int check(int* a) { int* restrict b = gimme_a_pointer(); int val = *b; black_box(val); *a = 42; return *b; }
Embed this notice
Max (goldstein@im-in.space)'s status on Sunday, 10-Nov-2024 06:54:26 JST Max
in reply to

GCC (but not Clang) also seems to ignore restrict on a func param, for a reason I can’t comprehend since PARM_NOALIAS shows up in pass details: https://godbolt.org/z/Yr475sn7z
In conversation about 17 days ago from im-in.space permalink
Attachments
1. Domain not in remote thumbnail source whitelist: raw.githubusercontent.com
  
  Compiler Explorer - C
  
  from Matt Godbolt
  
  void black_box(int); int* gimme_a_pointer(void); int check(int* a,int *restrict b) { int val = *b; black_box(val); *a = 42; return *b; }
Embed this notice
Max (goldstein@im-in.space)'s status on Saturday, 02-Nov-2024 05:39:11 JST Max
in reply to
- pinskia
- feedable
@pinskia a friend (@feedable) tinkered with it for a bit and found that it’s stuck in find_flexarrays, presumably because this computation isn’t cached

In conversation about a month ago from im-in.space permalink
Embed this notice
Max (goldstein@im-in.space)'s status on Saturday, 02-Nov-2024 02:25:24 JST Max
in reply to
- pinskia
@pinskia I tried that with -fsyntax-only, so that’s probably a frontend issue? I’m not sure where syntax-only compilation stops.

In conversation about a month ago from im-in.space permalink
Embed this notice
Max (goldstein@im-in.space)'s status on Friday, 01-Nov-2024 10:15:21 JST Max

TIL that neither GCC (in C or C++ mode) nor Clang (in C++ mode) can compile code like
struct f01 { int a, b; };
struct f02 { f01 a, b; };
struct f03 { f02 a, b; };
/* repeat a couple dozen times */

int main() {
f36 funny;
memset(&funny, 0, sizeof(funny));
}
in reasonable time (and compilation time grows exponentially with the number of nesting layers)

In conversation about a month ago from im-in.space permalink
Embed this notice
Max (goldstein@im-in.space)'s status on Thursday, 03-Aug-2023 21:02:58 JST Max
- GNU Parallel
TIL the latest (20230722) GNU Parallel version is named “Приго́жин” for some reason.
https://savannah.gnu.org/news/?id=10493
I tried to search for more info on why @GNU_Parallel would do that, but didn’t find anything substantial. parallel’s mailing list just announces it like it’s a perfectly normal name without any reasoning behind this choice.

In conversation Thursday, 03-Aug-2023 21:02:58 JST from im-in.space permalink

Public

Notices by Max (goldstein@im-in.space)

User actions

Following 0

Followers 0

Groups 0

Statistics

Feeds