Committed the following change:
http://gcc.gnu.org/r195424
* config/avr/avr.c (avr_out_fract): Make register numbers that
might be outside of source operand signed.
The problem occurs with fixed-point conversions to a wider mode and where the
input operand is in a small regno like r2:
src: QQmode in r2
dest: DAmode in r2
avr.c:avr_out_fract loops over the registers and clears dest registers at the
low end that have no associated src register (zero-extension at the low end).
In the sample case the register numbers (variables s0, s1) drop below 0 and
must be signed for that reason. Otherwise, some dest registers, starting at
2^{-16}, will not be cleared.
Johann
