diff options
| author | Chuck Atkins <chuck.atkins@kitware.com> | 2016-06-28 22:32:02 -0400 |
|---|---|---|
| committer | Tim Rowley <timothy.o.rowley@intel.com> | 2016-06-30 17:04:41 -0500 |
| commit | d8d6091a846ac2a40a011d512d6d57f6c8442e6a (patch) | |
| tree | 2a3e233fc4a8d15da0bb4f30b1a1d71004171e77 /src | |
| parent | c1bf6692beb662e5749e5680e0ebd15af2cd032a (diff) | |
gallium: Force blend color to 16-byte alignment
This aligns the 4-element color float array to 16 byte boundaries. This
should allow compiler vectorizers to generate better optimizations.
Also fixes broken vectorization generated by Intel compiler.
v2: Fixed indentation and added a lengthy comment explaining the
reason for the alignment.
Cc: <mesa-stable@lists.freedesktop.org>
Reported-by: Tim Rowley <timothy.o.rowley@intel.com>
Tested-by: Tim Rowley <timothy.o.rowley@intel.com>
Signed-off-by: Chuck Atkins <chuck.atkins@kitware.com>
Acked-by: Roland Scheidegger <sroland@vmware.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/gallium/include/pipe/p_state.h | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/gallium/include/pipe/p_state.h b/src/gallium/include/pipe/p_state.h index 1543e90972e9..5526c392aa70 100644 --- a/src/gallium/include/pipe/p_state.h +++ b/src/gallium/include/pipe/p_state.h @@ -326,7 +326,17 @@ struct pipe_blend_state struct pipe_blend_color { - float color[4]; + /** + * Making the color array explicitly 16-byte aligned provides a hint to + * compilers to make more efficient auto-vectorization optimizations. + * The actual performance gains from vectorizing the blend color array are + * fairly minimal, if any, but the alignment is necessary to work around + * buggy vectorization in some compilers which fail to generate the correct + * unaligned accessors resulting in a segfault. Specifically several + * versions of the Intel compiler are known to be affected but it's likely + * others are as well. + */ + PIPE_ALIGN_VAR(16) float color[4]; }; |