[Bug middle-end/78977] [7 Regression] g++7 snprintf() of double produces wrong code with -O3

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78977

--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
It's possible that this bug will be fixed by my patch for bug 78696.  The patch
was approved just before the holidays but I am yet to commit it.  Let me retest
it and check it in today.