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

[h2+bugs at fsfe dot org]

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

--- Comment #10 from Hannes Hauswedell <h2+bugs at fsfe dot org> ---
Created attachment 40454
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40454&action=edit
intermediate for O3 -fno-printf-return-value