Re: Build with LTO / -flto on macOS

Re: Tom Lane
> I fear that #2 is actually a pretty serious concern.  I think there
> are a lot of places where we've assumed semi-implicitly that
> compilation file boundaries are optimization barriers, particularly
> around stuff like LWLocks and semaphores.  I don't really want to
> spend time chasing obscure, irreproducible bugs that may appear when
> that assumption gets broken.  I especially don't want to do it just
> because some packager has randomly decided to inject random build
> switches.

Ubuntu enabled -ftlo=auto by default in 22.04, so it has been around
for some time already.

$ dpkg-buildflags
CFLAGS=-g -O2 -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -ffile-prefix-map=... -flto=auto -ffat-lto-objects
-fstack-protector-strong-fstack-clash-protection -Wformat -Werror=format-security -fcf-protection
-fdebug-prefix-map=...

Christoph