GCC-How does the coding style affect the insv pattern recognization?

[fanqifei]

2010/1/18 Adam Nemet <adambnemet@gmail.com>:
> Sorry for jumping in late.  See make_file_assigment in combine.c.
>
> The problem usually is that:
>
>  (set A (ior (and B C1) OTHER))
>
> can only be turned into a bit-insertion if A and B happen to be the same
> pseudos.
>
> Adam
>
Thank you, Adam.  The problem is that before combine pass the
statement is expressed in 6 insns. The insns can't be combined into
the expected pattern (set A (ior (and B C1) OTHER)). Otherwise,
make_field_assignment can do the job of simplifying the SET insn.

Qifei Fan