Code generation clarification (Submodels)

[Andrew Walrond]

Simple question, but I'm not entirely clear from reading the documentation

If I have a gcc configured for i686-* target system and I use that compiler to 
build a package without any -m submodel options , is the generated code
 1) only suitable for i686 and better, or
 2) tuned for i686 and better but still OK for i386

I know I can select exactly what I want with -m options, but what is the 
default for code generation?

Whatever the answer, is it a generic rule that holds true for submodels of all 
architectures?

What about 32bit code generated with x86_64 targeted gcc (with -m32)?

Andrew Walrond