[Bug tree-optimization/106922] [12 Regression] Bogus uninitialized warning on boost::optional<<std::vector<std::string>>>, missed FRE

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106922

--- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 53597
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53597&action=edit
candidate patch

For reference this is the patch I was talking about.  I'm sure I've made a
mistake in reasoning but I've not yet nailed it ;)

Let's leave the issue in this PR.

If you have spare cycles to do another bisection that might help as well.  If
your real code doesn't use LTO then bisecting preprocessed source from the
affected TU might be also interesting (but I suppose the issue might affect
multiple TUs?)