Re: [PATCH 1/3] sparc: build with -mvis on sparc32/sparcv9 and sparc64

[Aurelien Jarno <aurelien at aurel32 dot net>]

On 2016-08-04 07:29, Mike Frysinger wrote:
> On 04 Aug 2016 03:08, Aurelien Jarno wrote:
> > When building for sparc32/sparcv9 or sparc64, we assume that VIS
> > instructions are available and use them in the sparc specific assembly
> > code. However we do not tell GCC to use such instructions, resulting in
> > slightly suboptimal code.
> > 
> > Fix that by passing -Wa,-Av9a -mvis to GCC.
> 
> does this address:
> 	https://sourceware.org/bugzilla/show_bug.cgi?id=19477

Depends what you mean by address. The issue will disappear for sure.
However the real issue seems to be a misconfiguration between binutils
and GCC. The GCC call doesn't force any specific architecture, so it
means GCC is configure to default to v9a, while binutils is configured
for v9.

> it also seems to imply that v9 is *not* supported, and if you want to
> build for sparc64, you must have at least v9a ?  and that VIS is always
> supported ?  glancing at some wiki history, it doesn't seem like a big
> problem, but it is different from before.

Yes we have v9a code for example in sparc/sparc64/memset.S for more than
17 years, so it means v9 is not support since at least that time. Now I
do wonder if pure v9 CPUs (ie v9 without VIS) have ever existed.

Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net

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