[Bug rtl-optimization/78883] [avr] ICE triggered by change to combine.c (r243578)

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78883

--- Comment #2 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Created attachment 40389
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40389&action=edit
.combine dump as requested.

Genrated with

$ avr-gcc pr26833.c -S -O1 -mmcu=avr4 -S -fdump-rtl-combine-details

FYI, the error goes away with -Os or -O2.