Subject: bug#76559: 31.0.50; [-O3 + PGTK] Crash when 'copying as kill'/'killing word'

From: Po Lu <[email-masked]>
Date: Thu, 27 Feb 2025 21:30:36 +0800

Eli Zaretskii <[email-masked]> writes:

>> Date: Thu, 27 Feb 2025 12:22:36 +0000
>> From: Pip Cet <[email-masked]>
>> Cc: Po Lu <[email-masked]>, [email-masked],
>> [email-masked], [email-masked], [email-masked],
>> Stefan Kangas <[email-masked]>, Paul Eggert
>> <[email-masked]>
>> 
>> "Eli Zaretskii" <[email-masked]> writes:
>> 
>> > I believe we should recommend against using -O3.  Too many bad bugs
>> 
>> If we do that, can we include link time optimization in that?  I find
>> LTO'd code extremely difficult to read, since things like the calling
>> convention no longer apply (even when a function call isn't inlined, LTO
>> can still conclude that some registers survive the call and reuse them
>> even though the calling convention disagrees).

It's marginally easier to read the RTL (which ultimately becomes no more
than a Lisp-like representation of the assembly but with some tree
expressions and analogous details preserved for reference,
e.g. non-inlined procedure calls).

> Maybe we should also recommend against LTO.  Paul, WDYT about this?

I think there is no occasion to compile Emacs with any optimization
options besides -O2.