> I am checking in the patch below to the mainline and 4.6 branch. It
> disables the peephole optimizations in the rx.md file that combine a
> load followed by a zero- or sign- extend operation. The disabling
> only happens at -O3 (or higher) as although the peepholes reduce the
> number of instructions they can introduce pipeline stalls that
> actually make the program slower. (This is certainly true for the
> coremark test).
Doesn't that mean it should be disabled for any optimization other than
optimize_size? It seems surprising to have a "size but not speed" optimization
done at -O2.
paul
