https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64247
Ondrej Bilka <neleai at seznam dot cz> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |neleai at seznam dot cz --- Comment #7 from Ondrej Bilka <neleai at seznam dot cz> --- That looks like invalid bug. Fortran allows reassociate a+(b+c) into (a+b)+c which give different result. You will get same instability if you compile program with different versions of gcc.