Subject: bug#24720: Performance impact of -no-pie

From: Alex <[email-masked]>
Date: Tue, 18 Oct 2016 22:41:02 -0600

Glenn Morris <[email-masked]> writes:

> All that adding -no-pie does is restore the old default behaviour.
> It therefore makes no sense for it to cause a slowdown.

That makes sense.

> I'm going to guess that when you set it via CFLAGS, you lost the -O2
> that is otherwise part of the default CFLAGS.

That's indeed the case. I thought that specifying it when calling
./configure would have just added to the default CFLAGS instead of
overwriting it. Sorry for the false report.

> M-x report-emacs-bug includes information that would probably have
> made this obvious from the outset. Check the setting of CFLAGS in
> src/Makefile.

No, without specifying any CFLAGS manually, report-emacs-bug doesn't
mention any configuration details. This appears to be because
system-configuration-options is empty in that case.

Only when manually specifying flags does report-emacs-bug show the
configuration option section.

I can see what the CFLAGS are in src/Makefile, thanks. Though it might
be nice if I could see these at the Elisp level even when they're the
default.