[Bug c/105449] suspicious optimization since GCC 10.1.0 from -

[gilles.gouaillardet at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105449

--- Comment #1 from Gilles Gouaillardet <gilles.gouaillardet at gmail dot com> 
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Created attachment 52916
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52916&action=edit
a simple reproducer