[FFmpeg-trac] #10010(fate:new): Flacky test checkasm-float_dsp on i386 for 4.1.10

[FFmpeg]

#10010: Flacky test checkasm-float_dsp on i386 for 4.1.10
------------------------------+---------------------------------------
             Reporter:  Beuc  |                     Type:  defect
               Status:  new   |                 Priority:  normal
            Component:  fate  |                  Version:  unspecified
             Keywords:        |               Blocked By:
             Blocking:        |  Reproduced by developer:  0
Analyzed by developer:  0     |
------------------------------+---------------------------------------
 Hi, I'm in the process of uploading ffmpeg-4.1.10 to Debian (no patches),
 and I noticed a flacky test "checkasm-float_dsp" on i386:
 https://buildd.debian.org/status/fetch.php?pkg=ffmpeg&arch=i386&ver=7%3A4.1.10-0%2Bdeb10u1&stamp=1667560164&raw=0
 {{{
 Test checkasm-float_dsp failed. Look at tests/data/fate/checkasm-
 float_dsp.err for details.
  - float_dsp.vector_dmul         [FAILED]
 }}}

 How to reproduce:
 {{{
 # [build ffmpeg in i386 box or chroot]
 # gcc -dumpmachine
 i686-linux-gnu
 # ./configure
 # make tests/checkasm/checkasm
 # tests/checkasm/checkasm --test=float_dsp
 checkasm: using random seed 3387371545
 SSE:
  - float_dsp.vector_fmul         [OK]
  - float_dsp.vector_fmac         [OK]
  - float_dsp.butterflies_float   [OK]
  - float_dsp.scalarproduct_float [OK]
 217: -133.419753837637 - -133.419753837637 =  2.84217094304e-14
 SSE2:
    vector_dmul_sse2 (float_dsp.c:79)
  - float_dsp.vector_dmul         [FAILED]
  - float_dsp.vector_dmac         [OK]
 AVX:
  - float_dsp.vector_fmul         [OK]
  - float_dsp.vector_fmac         [OK]
  - float_dsp.vector_dmul         [OK]
  - float_dsp.vector_dmac         [OK]
 FMA3:
  - float_dsp.vector_fmul         [OK]
  - float_dsp.vector_fmac         [OK]
  - float_dsp.vector_dmac         [OK]
 AVX2:
  - float_dsp.vector_fmul         [OK]
 checkasm: 1 of 22 tests have failed
 }}}

 The test fails around 1 time out of 10.

 In case that helps, other kind of extra output when failing:
 {{{
 151: -403.760630477823 - -403.760630477823 =  5.68434188608e-14
 172:  45.559144693618 -  45.559144693618 = -7.1054273576e-15
 188: -117.340568240766 - -117.340568240766 = -1.42108547152e-14
 237: -4.352744435243 - -4.352744435243 =  8.881784197e-16
 }}}
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/10010>
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