<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 TRANSITIONAL//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=UTF-8"> <META NAME="GENERATOR" CONTENT="GtkHTML/3.26.0"> </HEAD> <BODY> On Wed, 2010-02-24 at 11:58 -0800, Jeremy Huddleston wrote: <BLOCKQUOTE TYPE=CITE> <PRE> On Feb 24, 2010, at 05:45, Gaetan Nadon wrote: > On Wed, 2010-02-24 at 09:34 +0100, Michel Dänzer wrote: > >> On Tue, 2010-02-23 at 11:11 -0800, Jeremy Huddleston wrote: >>> On Feb 23, 2010, at 11:07, Keith Packard wrote: >>> >>>> On Tue, 23 Feb 2010 13:37:18 -0500, Gaetan Nadon >>>> <<A HREF="mailto:memsize@videotron.ca">memsize@videotron.ca</A>> wrote: >>>> >>>>> This patch will ensure the xserver continues to suppress the >>>>> optimization, based on strict aliasing rules, after the option >>>>> is removed from $CWARNFLAGS. There is no change in the object >>>>> code produced. >>>> >>>> I don't think we need to allow any of the code in the X server to be >>>> 'optimized' in this fashion, so I don't see a need to allow for >>>> per-directory selection. >>> >>> It would be helpful if I had the option to remove this flag from >>> XQuartz. >> >> Out of curiosity, what significant benefit have you measured from using >> -fstrict-aliasing? >> >> > > Excellent question which I carefully want to avoid :-) > > The problem I want to solve is the following: someone added > -fnostrict-aliasing a long time ago and I don't know why. Then it got > copied to a number of libraries, then got included in a macro > (XORG_CWARNFLAGS), which then got included by over a hundred modules, > still not knowing why. > > There are over 50 modules that are compiling with no warning flags at > all. I don't want to contribute to the spread of this option. The patch > is about *transferring* the option out of the macro back to the modules > (where the skills are) and let them decide if they want that option or > not. Additionally, before being copied into XORG_CWARNFLAGS fairly recently, this was only in a handful of modules: libICE libSM libX11 libXau libXfont libXft libXpm libXres xorg-server (I didn't check xf86-drivers) So adding it across the board is rather far-reaching, IMO. I believe it should only be added back to the modules listed above. </PRE> </BLOCKQUOTE> For the sole purpose of providing information: Modules which had CWARNFLAGS added a year ago *and* did not have -fno-strict-aliasing option prior to that: <BLOCKQUOTE> <PRE> font= "util" app= "appres bdftopcf beforelight bitmap editres fonttosfnt fslsfonts fstobdf iceauth \ ico listres luit mkcomposecache mkfontscale oclock rendercheck rgb rstart  sessreg setxkbmap \ showfont smproxy viewres x11perf xauth xbacklight xbiff xcalc xclipboard xclock xcmsdb xconsole \ xcursorgen xdbedizzy xdm xdpyinfo xdriinfo xedit xev xeyes xf86dga xfd xfontsel xfs xfsinfo \ xgamma xgc xhost xinit xkbcomp xkbevd xkbprint xkbutils xkill xload xlogo xlsatoms xlsclients \ xlsfonts xmag  xman xmessage xmh xmodmap xmore xprop xrandr xrdb xrefresh xscope xset xsetmode \ xsetpointer xsetroot xsm xstdcmap xvidtune xvinfo xwd xwininfo xwud" lib=" libAppleWM libdmx libfontenc libFS libpciaccess libWindowsWM \ libXaw libXcomposite libXcursor libXdamage libXdmcp libXext \ libXfixes libXi libXinerama libxkbfile libXmu libXrandr \ libXrender libXScrnSaver libXt libXtst libXv libXvMC \ libXxf86dga" driver="xf86-input-acecad xf86-input-aiptek xf86-input-evdev \ xf86-input-joystick xf86-input-keyboard xf86-input-mouse \ xf86-input-wacom xf86-video-cirrus xf86-video-mach64 \ xf86-video-qxl xf86-video-siliconmotion" </PRE> </BLOCKQUOTE> Modules which never had -fno-strict-aliasing nor any warning flags of any kind and still don't today: <BLOCKQUOTE> <PRE> app="mkfontdir scripts twm xditview xinput" lib="libXxf86vm" driver="xf86-input-synaptics xf86-input-vmmouse \ xf86-input-void xf86-video-apm xf86-video-ark \ xf86-video-ast xf86-video-ati xf86-video-chips \ xf86-video-dummy xf86-video-fbdev\ xf86-video-glint xf86-video-i128 xf86-video-i740 \ xf86-video-mga xf86-video-neomagic xf86-video-newport \ xf86-video-nv xf86-video-r128 \ xf86-video-rendition xf86-video-s3 xf86-video-s3virge \ xf86-video-savage xf86-video-sis xf86-video-sisusb \ xf86-video-suncg14 xf86-video-suncg3 xf86-video-suncg6 \ xf86-video-sunffb xf86-video-sunleo xf86-video-suntcx \ xf86-video-tdfx xf86-video-tga xf86-video-trident \ xf86-video-tseng xf86-video-v4l xf86-video-vesa \ xf86-video-vmware xf86-video-voodoo xf86-video-wsfb \ xf86-video-xgi xf86-video-xgixp " </PRE> </BLOCKQUOTE> Modules which had -fno-strict-aliasing for a long time (prior to CWARNFLAGS era) <BLOCKQUOTE> <PRE> lib="libICE libSM libX11 libXau libXfont libXft libXpm libXres" driver="xf86-video-intel xf86-video-geode xf86-video-radeonhd" xserver </PRE> </BLOCKQUOTE> My next task is to add warning flags to those modules who don't. If we wish to preserve status quo (for aliasing), I can define a new variable, leaving CWARNFLAGS intact so older versions of modules configured against newer versions of macros aren't affected. </BODY> </HTML>