xf. http://gcc.gnu.org/ml/gcc/2008-05/msg00274.html
> Why is store_motion doing this?
>
> STORE_MOTION delete insn in BB 2:
> (insn 8 7 27 2 dj.c:10 (parallel [
> (set (mem/s/j:HI (reg/v/f:HI 26 [ s ]) [0
> <variable>.buf+0 S2 A8])
> (ashift:HI (reg/v:HI 27 [ n ])
> (subreg:QI (reg/v:HI 27 [ n ]) 0)))
> (clobber (scratch:HI))
> ]) 223 {ashlhi3_i} (expr_list:REG_DEAD (reg/v:HI 27 [ n ])
> (nil)))
> STORE MOTION replaced with insn:
> (insn 27 8 9 2 dj.c:10 (set (reg:HI 29 [ <variable>.buf ])
> > (ashift:HI (reg/v:HI 27 [ n ])
> (subreg:QI (reg/v:HI 27 [ n ]) 0))) -1
> (expr_list:REG_DEAD (reg/v:HI 27 [ n ])
> (nil)))
This insn is generated by gen_move_insn in gcse.c:replace_store_insn().
Maybe that should be emit_move_insn()?
Gr.
Steven
