You're not always being very constructive yourself, you know...
Anyway, here's something you could do.
- get preprocessed sources of a full gcc build tree. You can do
that by bootstrapping with -save-temps, and then collect all
the .i and .ii files in one place.
- do "for $f in *.i; \
do $build/gcc/cc1 -quiet -fdump-tree-optimized -O2 $f; \
done". Do the same for all .ii files. Do this for a patched
and an unpatched compiler, and compare all the .optimized files.
If they are identical, you've taken the first hurdle.
- hack the test suite scripts to dump the .optimized tree dump in
some directory (but *not* the $build/gcc/testsuite/ directory)
Do this again for the patched and unpatched compilers, and again
compare them.