[Mesa-stable] [Mesa-dev] [PATCH v3] llvmpipe: disable VSX in ppc due to LLVM PPC bug

[Roland Scheidegger]

Am 17.11.2015 um 21:35 schrieb Oded Gabbay:
> This patch disables the use of VSX instructions, as they cause some
> piglit tests to fail
> 
> For more details, see: https://llvm.org/bugs/show_bug.cgi?id=25503#c7
> 
> With this patch, ppc64le reaches parity with x86-64 as far as piglit test
> suite is concerned.
> 
> v2:
> - Added check that we have at least LLVM 3.4
> - Added the LLVM bug URL as a comment in the code
> 
> v3:
> 
> - Only disable VSX if Altivec is supported, because if Altivec support
> is missing, then VSX support doesn't exist anyway.
> 
> - Change original patch description.
> 
> Signed-off-by: Oded Gabbay <oded.gabbay at gmail.com>
> Cc: "11.0" <mesa-stable at lists.freedesktop.org>
> ---
>  src/gallium/auxiliary/gallivm/lp_bld_misc.cpp | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
> index 7bda118..3ee708f 100644
> --- a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
> +++ b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
> @@ -536,6 +536,15 @@ lp_build_create_jit_compiler_for_module(LLVMExecutionEngineRef *OutJIT,
>  
>  #if defined(PIPE_ARCH_PPC)
>     MAttrs.push_back(util_cpu_caps.has_altivec ? "+altivec" : "-altivec");
> +#if HAVE_LLVM >= 0x0304
> +   /*
> +    * Make sure VSX instructions are disabled
> +    * See LLVM bug https://llvm.org/bugs/show_bug.cgi?id=25503#c7
> +    */
> +   if (util_cpu_caps.has_altivec) {
> +      MAttrs.push_back("-vsx");
> +   }
> +#endif
>  #endif
>  
>     builder.setMAttrs(MAttrs);
> 

Reviewed-by: Roland Scheidegger <sroland at vmware.com>