Re: [PATCH] arch-armv7a.inc: default to Thumb2 instruction set for armv7a and above

[<Jef.Driesen@niko.eu>]

Andre McCurdy wrote:
> Although there may still be specific cases which can benefit from the
> ARM instruction set, the Thumb2 instruction set is generally a better
> default for armv7a class CPUs. Distros such as Debian and Fedora have
> been targeting Thumb2 by default for some time.
>
> Note that setting ARM_INSTRUCTION_SET has no effect unless
> TUNE_FEATURES contains "thumb" (which is controlled by the "t" suffix
> in DEFAULTTUNE, e.g. armv7vehf-neon -vs- armv7vethf-neon, etc) so out
> of tree machine configs may need to update their DEFAULTTUNE to take
> advantage of this change.

I recently ran into some major problems due to thumb vs arm. It turns out glibc doesn't support systems with thumb disabled anymore. See this bug report for details:

https://sourceware.org/bugzilla/show_bug.cgi?id=23031

This might be useful input for this discussion also.

Jef
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