https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71618
--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> --- (In reply to Manuel López-Ibáñez from comment #3) Good idea. Thanks. I think it might help set the right expectation if this detail was more succinctly mentioned in the manual itself. For instance, under the -O options, by changing: -O turns on the following optimization flags: ... to -O turns on the optimization flags below. It may also enable additional optimizations that aren't controlled by individual flags on which the listed optimizations depend. As a result, the effect of -O is not the same as specifying all of the flags on the list.
