Hi,
On 2023-11-28 20:58:41 -0500, Andrew Dunstan wrote:
> On 2023-11-28 Tu 19:32, Tom Lane wrote:
> > Andrew Dunstan <andrew@dunslane.net> writes:
> > So I'm now a bit baffled. Can you provide more color on what
> > your test setup is?
>
>
> *sigh* yes, you're right. I inadvertently used a setup that used meson for
> building REL16_STABLE and HEAD. When I switch it to autoconf I get results
> that are similar to the earlier branches:
>
>
> ==== REL_16_STABLE ====
> Time: 3401.625 ms (00:03.402)
> ==== HEAD ====
> Time: 3419.088 ms (00:03.419)
>
>
> It's not clear to me why that should be. I didn't have assertions enabled
> anywhere. It's the same version of bison, same compiler throughout. Maybe
> meson sets a higher level of optimization? It shouldn't really matter, ISTM.
Is it possible that you have CFLAGS set in your environment? For reasons that
I find very debatable, configure.ac only adds -O2 when CFLAGS is not set:
# C[XX]FLAGS are selected so:
# If the user specifies something in the environment, that is used.
# else: If the template file set something, that is used.
# else: If coverage was enabled, don't set anything.
# else: If the compiler is GCC, then we use -O2.
# else: If the compiler is something else, then we use -O, unless debugging.
if test "$ac_env_CFLAGS_set" = set; then
CFLAGS=$ac_env_CFLAGS_value
elif test "${CFLAGS+set}" = set; then
: # (keep what template set)
elif test "$enable_coverage" = yes; then
: # no optimization by default
elif test "$GCC" = yes; then
CFLAGS="-O2"
else
# if the user selected debug mode, don't use -O
if test "$enable_debug" != yes; then
CFLAGS="-O"
fi
fi
So if you have CFLAGS set in the environment, we'll not add -O2 to the
compilation flags.
I'd check what the actual flags are when building a some .o.
Greetings,
Andres Freund