[Bug inline-asm/11203] source doesn't compile with -O0 but they compile with -O3

["michaelni at gmx dot at" <gcc-bugzilla@gcc.gnu.org>]

------- Additional Comments From michaelni at gmx dot at  2005-01-01 18:57 -------
(In reply to comment #12)
> Why do people write inline-asm like this?

why not? its valid code and a compiler should compile valid code ...


> It is crazy to do so.  Split up the inline-asm correctly.

fix gcc first so it doesnt load&store more then needed between the splited up parts


> Anyone who writes like inline-asm should get what they get.
> For mmx inline-asm, you should be using the intrinsics instead as suggested before

lets see why its not using intrinsics
* it was written before intrinsics support was common
* intrinsics fail / get misscompiled commonly, its so bad that some of the
altivec intrinsic code has been disabled in ffmpeg if standard gcc is detected,
there also have been very serious and similar problems in mplayer with
altivec-intrinsics, sadly i cant provide more details as i dont have a ppc
* many if not most of the mplayer developers still use gcc 2.95 because gcc 3.*
is slower and needs more memory, and AFAIK 2.95 doesnt support intrinsics
* it is alot of work to rewrite and debug it just to make it compileable with
gcc -O0


> or just write real asm file.

thats not a good idea either as:
* its slower due to the additional call/ret/parameter passing
* there are some symbol name mangling issues on some obscure systems (see
mplayer-dev or cvslog mailinglist, it was disscussed there a long time ago)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11203