[FFmpeg-cvslog] x86/tx_float: save a branch during coefficient deinterleaving

[Lynne]

ffmpeg | branch: master | Lynne <dev at lynne.ee> | Tue Aug  9 03:31:11 2022 +0200| [98b32ef462ba344b99034f7f85c2d66cfd7f0055] | committer: Lynne

x86/tx_float: save a branch during coefficient deinterleaving

Directly branch into the special 64-point deinterleave
subroutine rather than going through the general deinterleave.

64-point transform timings on Zen 3:
Before:
   1974 decicycles in           av_tx (fft),16776864 runs,    352 skips
After:
   1956 decicycles in           av_tx (fft),16775378 runs,   1838 skips

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=98b32ef462ba344b99034f7f85c2d66cfd7f0055
---

 libavutil/x86/tx_float.asm | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/libavutil/x86/tx_float.asm b/libavutil/x86/tx_float.asm
index 21f99d3945..191af7d68f 100644
--- a/libavutil/x86/tx_float.asm
+++ b/libavutil/x86/tx_float.asm
@@ -1044,7 +1044,7 @@ ALIGN 16
     add lutq, (mmsize/2)*8
 %endif
     cmp tgtq, 64
-    je .deinterleave
+    je .64pt_deint
 
     SPLIT_RADIX_COMBINE_64
 
@@ -1190,9 +1190,6 @@ FFT_SPLIT_RADIX_DEF 131072
 ; Final synthesis + deinterleaving code
 ;===============================================================================
 .deinterleave:
-    cmp lenq, 64
-    je .64pt_deint
-
     imul tmpq, lenq, 2
     lea lutq, [4*lenq + tmpq]