[Bug target/83133] Superflous x86 test instructions in generated assembly.

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83133

--- Comment #5 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
Both 32-bit and 64-bit ABIs make the values of flags in EFLAGS (other than 
DF) undefined on function entry and return.  Thus, a function can never 
assume anything about the value of OF unless it has executed an 
instruction known to set/clear it and has not called any other functions 
since then.