[Mesa-dev] [Mesa-stable] [PATCH v2] llvmpipe: disable vsx in ppc due to LLVM PPC bug

[Emil Velikov]

On 17 November 2015 at 16:02, Oded Gabbay <oded.gabbay at gmail.com> wrote:
> This patch makes sure that if we use altivec (VMX) instructions, we don't
> use VSX instructions as well, as this cause 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
>
> 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 | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
> index 7bda118..152593a 100644
> --- a/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
> +++ b/src/gallium/auxiliary/gallivm/lp_bld_misc.cpp
> @@ -536,6 +536,10 @@ 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
> +   /* See LLVM bug https://llvm.org/bugs/show_bug.cgi?id=25503#c7 */
> +   MAttrs.push_back("-vsx");
The commit message does not reflect what the patch actually does. I
cannot object against the patch in any way, although the two should be
in sync imho.

Base of a very quick look at the llvm bug, I'm leaning that the commit
msg is correct and the patch is off ?

Thanks
Emil