As stated in: http://www.gentoo.org/doc/en/gcc-optimization.xml#doc_chap2 "This is a very common flag designed to reduce generated code size. It is turned on at all levels of -O (except -O0) on architectures where doing so does not interfere with debugging (such as x86-64), but you may need to activate it yourself by adding it to your flags. Though the GNU gcc manual does not specify all architectures it is turned on by using -O, you will need to explicitly activate it on x86. However, using this flag will make debugging hard to impossible. " This should be noted on amd64 handbook for preventing users to add this redundant flag Thanks a lot Reproducible: Always
Redundant flags are not a problem. We also don't tell users to set the flag in the AMD64 example, either. It's my experience that unless specifically told to add something, first time users don't generally deviate from the sample configs in the handbook. More advanced users do, and since they're advanced, they tend to already know about how CFLAGS work. I'd prefer to leave it as-is.
I don't fully agree but ok, I can leave with it :-) Thanks for fast reply