[Bug sanitizer/66908] Uninitialized variable when compiled with UBsan

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66908

--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I think I have a fix now.  The trick was to use unshare_expr.  Testing some
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