The answer to $subject is not at all urgent, but I noticed we can get
some (very modest) speed increases in the "pedantic" CI job when adding
-fsyntax-only to CFLAGS. This currently requires monkeypatching out the
"-o <target> -c" part hardcoded in the Makefile. See cebead1ebfb (ci:
run a pedantic build as part of the GitHub workflow, 2021-08-08) for the
pedantic job.
I.e. I'm aware of CFLAGS's -O<n> changing which warings we emit, but
does -fsyntax-only?
The gcc manpage suggests that it would, saying:
Check the code for syntax errors, but don't do anything beyond that
Whereas clang's says:
Run the preprocessor, parser and type checking stages.
I think gcc's is a case of its docs drifting out of sync with the
implementation. Both will warn on e.g. this program under -pedantic,
which gcc wouldn't be doing if it only did syntax parsing (and didn't
run the warning machinery):
int main(void)
{
int v[0];
return 0;
}
I don't have any practical use for this now. We could squeeze some
slight performance out of one CI jobs, but perhaps it'll be more
interesting in the future.
