[Bug middle-end/55889] [4.8 Regression] ICE: in move_op_ascend, at sel-sched.c:6153 with -fschedule-insns -fselective-scheduling

[abel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55889

--- Comment #26 from Andrey Belevantsev <abel at gcc dot gnu.org> 2013-02-01 12:22:05 UTC ---
You are right, your suggestions is what I sketched in comment #21 as choices 1
or 2.  Sorry for my unclear expalanation of what was actually happening.

I don't have a problem with making sel-sched have extra checks when renaming
registers before reload, which will make us notice a not obvious extra
dependence and avoid renaming properly, as now we've figured out these
dependences don't follow immediately from the RTL.  I just want an extra
opinion on whether such unexpected dependencies arising when a target (hard)
register is replaced by a pseudo register should be normal within GCC, or do we
attribute such dependencies only to the register pressure scheduling mode. 
FWIW, I would rather agree with the latter than with the former.