[arm64] Negative immediates and lack of default Neon support
marc.glisse at inria.fr
Wed Sep 24 18:04:40 UTC 2014
On Wed, 24 Sep 2014, Torbjörn Granlund wrote:
> Marc Glisse <marc.glisse at inria.fr> writes:
> I get:
> clang: warning: argument unused during compilation: '-mfpu=neon'
> for every call to clang, but it works.
> Well, they really do like pointless warnings over in clang land.
> We cannot fix this without desupporting some clang releases, since
> autoconf does not support having feature test results to be controlled
> by warning output.
Can't we compile something that will fail without neon and add -mfpu=neon
only in that case? Otherwise, the warning is bearable.
> By the way, for inline asm, the 'w' modifier you showed me is the
> official way and gcc is going to document that:
> This is a pity, since it makes it inconsistent with other gcc ports, and
> depending on gcc internals is not very clean. Furthermore, this creates
> an incompatibility trap between gcc and clang (which we just triggered,
> of course).
Actually, contrary to what I said yesterday, clang does support 'w' (I
still can't imagine what I may have done yesterday to get that wrong).
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