[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Bug gas/6957] i386 NOPs must be derived from march not mtune
From: |
hjl dot tools at gmail dot com |
Subject: |
[Bug gas/6957] i386 NOPs must be derived from march not mtune |
Date: |
12 Oct 2008 12:44:02 -0000 |
------- Additional Comments From hjl dot tools at gmail dot com 2008-10-12
12:44 -------
(In reply to comment #6)
> Created an attachment (id=2997)
--> (http://sourceware.org/bugzilla/attachment.cgi?id=2997&action=view)
> binutils-cvs-fix2-i386-nop.patch
>
> Add bitfield checking back to patch for .arch settings.
>
> First point, do you not first agree that choosing instructions based on mtune
> is seriously broken?
>
> The other point here is about compatibility. Yes, these CPUs are missing this
> one instruction but since most builds these days are i686 by default this will
> break on these systems for users. It's only been fortunate that GCC strips out
> mtune options to gas. The optimisation lost is minor.
>
> I'm obviously an unknown person but the link given shows Linus Torvalds
> opinion
> on this which may or not mean much to you.
For assembler, PROCESSOR_UNKNOWN means CPU will take any instructions,
including those new NOPs. If you want to limit NOPs to certain ISA,
XXX, you need to use -match=XXX/-mtune=XXX. I checked in a patch
http://sourceware.org/ml/binutils/2008-10/msg00124.html
Now you can use the .arch directive to limit NOPs to XXX.
--
http://sourceware.org/bugzilla/show_bug.cgi?id=6957
------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.
- [Bug gas/6957] New: i386 NOPs must be derived from march not mtune, swanson at ukfsn dot org, 2008/10/11
- [Bug gas/6957] i386 NOPs must be derived from march not mtune, swanson at ukfsn dot org, 2008/10/11
- [Bug gas/6957] i386 NOPs must be derived from march not mtune, hjl dot tools at gmail dot com, 2008/10/11
- [Bug gas/6957] i386 NOPs must be derived from march not mtune, swanson at ukfsn dot org, 2008/10/12
- [Bug gas/6957] i386 NOPs must be derived from march not mtune, hjl dot tools at gmail dot com, 2008/10/12
- [Bug gas/6957] i386 NOPs must be derived from march not mtune, hjl dot tools at gmail dot com, 2008/10/12
- [Bug gas/6957] i386 NOPs must be derived from march not mtune, swanson at ukfsn dot org, 2008/10/12
- [Bug gas/6957] i386 NOPs must be derived from march not mtune,
hjl dot tools at gmail dot com <=
- [Bug gas/6957] i386 NOPs must be derived from march not mtune, hjl dot tools at gmail dot com, 2008/10/12
- [Bug gas/6957] i386 NOPs must be derived from march not mtune, swanson at ukfsn dot org, 2008/10/12
- [Bug gas/6957] i386 NOPs must be derived from march not mtune, hjl dot tools at gmail dot com, 2008/10/12
- [Bug gas/6957] i386 NOPs must be derived from march not mtune, hjl dot tools at gmail dot com, 2008/10/12