tree a8c02da41e44d16cdcb28a02877ace20a6ddc78f
parent 6e13c69d6b2507a353e726b5a132ae4a0dd8cca8
author Alex Peterson <petersonab@google.com> 1627319042 -0700
committer James Zern <jzern@google.com> 1629419204 -0700

Add msan helper functions to common_neon.h

The implementation differs from x86 because the VEXT instruction is
a reversal of _mm_srli_si128. Instead of pulling zeroes from the back,
the mask pushes 0xFF bytes in from the front.

Usage in film_grain_neon.cc prevents use-of-uninitialized-value errors.

PiperOrigin-RevId: 386899807
Change-Id: I93fc6b246a8555521eb3c174ecc05961f15347c2