Uros Bizjak <[email protected]> writes:
> On Sat, Jul 16, 2011 at 6:47 PM, H.J. Lu <[email protected]> wrote:
>>>> Yes, this is an example from PR I am referring to. Did you try to
>>>> define LEGITIMIZE_RELOAD_ADDRESS? It is supposed to fix this.
>>>>
>>>
>>> They make things even more complex. ix86_simplify_base_index_disp
>>> is called after reload is done since we can do this translation safely
>>> only on hard registers, not on pseudo registers.
>>>
>>
>> Hi Uros,
>>
>> The current implementation has been tested extensively. I'd like to keep
>> it ASIS so that we can have a working x32 support. We will revisit it later:
>>
>> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49765
>>
>> after we have a working x32 GCC.
>
> This can not be only my decision, I have CCd other x86 maintainers and
> RMs for their opinion on this question.
FWIW, I agree with you that things like:
(set (reg:SI 40 r11)
(plus:SI (plus:SI (mult:SI (reg:SI 1 dx)
(const_int 8))
(subreg:SI (plus:DI (reg/f:DI 7 sp)
(const_int CONST1)) 0))
(const_int CONST2)))
do not look like things that should ever enter the insn stream.
They're liable to confuse other code besides the x86 predicates.
The target of the conversion:
(set (reg:SI 40 r11)
(plus:SI (plus:SI (mult:SI (reg:SI 1 dx)
(const_int 8))
(reg/f:SI 7 sp))
(const_int [CONST1 + CONST2])))
looks like the generally preferred form. It isn't an x32-ism.
LEGITIMIZE_RELOAD_ADDRESS is supposed to be for optimisation only,
not correctness. Why doesn't reload have enough information to
generate the correct form itself?
Richard
