[Bug tree-optimization/92980] [miss optimization]redundant load missed by fre.

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92980

--- Comment #8 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Andrew Pinski from comment #4)

> But that is not true any more.  So I think this optimization can be removed
> as it is too early.  Just double check the above testcase and the C++
> testcase (g++.dg/opt/ptrintsum1.C) to make sure they still work and post
> that removal.  This optimization is most likely causing other missed
> optimizations already too.  So I would compile SPEC to see if there is any
> differences; my bet you might find some.

No big impact for SPEC2017, more or less like noise.

500.perlbench_r 0.21%
502.gcc_r       0.14%
505.mcf_r       -0.40%
520.omnetpp_r   -0.47%
523.xalancbmk_r -1.20%
525.x264_r      -1.26%
531.deepsjeng_r -0.05%
541.leela_r     -0.39%
548.exchange2_r -0.09%
557.xz_r        -0.16%
geomean for intrate     -0.37%
503.bwaves_r    -0.19%
507.cactuBSSN_r 0.23%
508.namd_r      -0.12%
510.parest_r    0.18%
511.povray_r    -0.30%
519.lbm_r       BuildSame       #VALUE!
521.wrf_r       -0.01%
526.blender_r   -0.44%
527.cam4_r      -0.17%
538.imagick_r   0.47%
544.nab_r       -1.00%
549.fotonik3d_r 0.09%
554.roms_r      0.28%
geomean for fprate      -0.08%
geomean -0.21%