Re: The Emacs master is much slower than the emacs-27 branch.

[Óscar Fuentes]

Stephen Berman <stephen.berman@gmx.net> writes:

> emacs-27:
>
> system-configuration-options
> "'CFLAGS=-Og -g3' PKG_CONFIG_PATH=/opt/qt5/lib/pkgconfig"
>
> system-configuration-features
> "XPM JPEG TIFF GIF PNG RSVG SOUND DBUS GSETTINGS GLIB NOTIFY INOTIFY ACL
> GNUTLS LIBXML2 FREETYPE HARFBUZZ XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11
> XDBE XIM MODULES THREADS LIBSYSTEMD PDUMPER LCMS2 GMP"
>
> master:
>
> system-configuration-options
> "--with-xwidgets 'CFLAGS=-Og -g3' PKG_CONFIG_PATH=/opt/qt5/lib/pkgconfig"
>
> system-configuration-features
> "XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND DBUS GSETTINGS GLIB NOTIFY
> INOTIFY ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ ZLIB TOOLKIT_SCROLL_BARS
> GTK3 X11 XDBE XIM MODULES THREADS XWIDGETS LIBSYSTEMD PDUMPER LCMS2"

Please correct me if I'm wrong, but overriding CFLAGS means that gcc
compiles with default optimization level, wich is -O0, hence you are
comparing unoptimized builds, right? In that case, a tiny change on some
often-used macro or function can make a big difference.