Bug#852153: gcc-6/mips: backport option to disable madd4 instructions and set it default

[Matthias Klose <doko@debian.org>]

Is this still targeted for stretch?

On 22.01.2017 04:19, YunQiang Su wrote:
> Package: src:gcc-6
> Version: 6.3.0-3
> 
> Hi, gcc-7 has added a new option to disable madd.fmt/msub.fmt etc instructions,
> as
>     1. For the MIPS standard, these instructions are unfused, while on Loongson,
>         they are fused. With these instructions enabled, some software
> may failed to
>         run on Loongson.
>      2. With some test, these instructions won't take significant
> performance boost.
> 
> So, we decide to disable these instructions at all.
> 
> In this patch, we also:
>       1. generate fused madd4 instructions when -march=loongson3a used.
>       2. add a new option: -mlxc1-sxc1.
>