Backend specific optimization for PPC VSX reads 16 bytes, whereas arm neon /
sse2 only reads <= 8 bytes. Although the extra bytes read are actually never
used, this is not a warrant for groping around. Fixed by allocating more when
building for VSX. This is reported by asan.
Also note - PPC does have assembly that loads 64-bit content from memory - lxsdx
loads one 64-bit doubleword (whereas lxvd2x loads two 64-bit doubleword) from
memory. However, we only have "vec_vsx_ld" builtins that mapped to lxvd2x, no
builtins to lxsdx. The only way to access lxsdx is through inline assembly,
which does not fit well in the origin paradigm.
Refer:
vsx:
vpx_tm_predictor_4x4_vsx @ third_party/libvpx/git_root/vpx_dsp/ppc/intrapred_vsx.c
neon:
vpx_tm_predictor_4x4_neon @ third_party/libvpx/git_root/vpx_dsp/arm/intrapred_neon_asm.asm
sse2:
tm_predictor_4x4 @ third_party/libvpx/git_root/vpx_dsp/x86/intrapred_sse2.asm
BUG=b/
63112600
Tested:
asan tests passed.
Change-Id: I5f74b56e35c05b67851de8b5530aece213f2ce9d
unsigned char *uleft, unsigned char *vleft, int left_stride,
unsigned char *upred_ptr, unsigned char *vpred_ptr, int pred_stride) {
MB_PREDICTION_MODE uvmode = x->mode_info_context->mbmi.uv_mode;
+#if HAVE_VSX
+ /* Power PC implementation uses "vec_vsx_ld" to read 16 bytes from
+ uleft_col and vleft_col. Play it safe by reserving enough stack
+ space here. */
+ unsigned char uleft_col[16];
+ unsigned char vleft_col[16];
+#else
unsigned char uleft_col[8];
unsigned char vleft_col[8];
+#endif
int i;
intra_pred_fn fn;
int left_stride, B_PREDICTION_MODE b_mode,
unsigned char *dst, int dst_stride,
unsigned char top_left) {
- unsigned char Aboveb[12], *Above = Aboveb + 4;
+/* Power PC implementation uses "vec_vsx_ld" to read 16 bytes from
+ Above (aka, Aboveb + 4). Play it safe by reserving enough stack
+ space here. Similary for "Left". */
+#if HAVE_VSX
+ unsigned char Aboveb[20];
+#else
+ unsigned char Aboveb[12];
+#endif
+ unsigned char *Above = Aboveb + 4;
#if HAVE_NEON
// Neon intrinsics are unable to load 32 bits, or 4 8 bit values. Instead, it
// over reads but does not use the extra 4 values.
// indeed read, they are not used.
vp8_zero_array(Left, 8);
#endif // VPX_WITH_ASAN
+#elif HAVE_VSX
+ unsigned char Left[16];
#else
unsigned char Left[4];
#endif // HAVE_NEON