Commit b9d4bd7271 for ffmpeg

commit b9d4bd727165a882fe3aa8e37ecb7ad82b3ecbbc
Author: Niklas Haas <git@haasn.dev>
Date:   Thu Oct 22 20:42:01 2026 +0200

    swscale/x86/ops_int: fix over-write in SSE4 WRITE_NIBBLE

    Without AVX2, a block only holds 8 bytes worth of nibbles, but the full
    XMM register was stored, clobbering 8 bytes past the end of the block.
    This corrupted the previous line for negative linesizes.

    Signed-off-by: Niklas Haas <git@haasn.dev>

diff --git a/libswscale/x86/ops_int.asm b/libswscale/x86/ops_int.asm
index 6f49ffeafe..692a3627ac 100644
--- a/libswscale/x86/ops_int.asm
+++ b/libswscale/x86/ops_int.asm
@@ -134,9 +134,12 @@ assert COMPS == 1
 %if cpuflag(avx2)
         vpermq mx, mx, q3120
 IF V2,  vpermq mx2, mx2, q3120
-%endif
         movu [out0q], xmx
 IF V2,  movu [out0q + (mmsize >> 1)], xmx2
+%else
+        movq [out0q], mx
+IF V2,  movq [out0q + (mmsize >> 1)], mx2
+%endif
         add out0q, BLOCK_WIDTH >> 1
         RET
 %endmacro