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
2 years ago · 98b32ef462
parent 5cdf4c0bed
commit 98b32ef462
1 changed files with 1 additions and 4 deletions
--- 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]