On Tue, Aug 27, 2013 at 9:02 AM, Hendrik Greving
<hendrik.greving.intel@xxxxxxxxx> wrote:
> Would you say that basically you're supposed to support that in terms
> of predicates so it 'passes' recog?
(Please don't top-post. Thanks.)
Yes, assuming your processor supports loading a full word immediate
into a register in a single instruction (e.g., x86 does support that,
MIPS does not).
Ian
> On Mon, Aug 26, 2013 at 10:50 PM, Ian Lance Taylor <iant@xxxxxxxxxx> wrote:
>> On Mon, Aug 26, 2013 at 7:51 PM, Hendrik Greving
>> <hendrik.greving.intel@xxxxxxxxx> wrote:
>>>
>>> GCC 4.8.1 generates a movsi like this when compiling newlib with my backend:
>>>
>>> gdb) call debug_rtx(operand0)
>>> (reg:SI 356)
>>> (gdb) call debug_rtx(operand1)
>>> (const:SI (plus:SI (symbol_ref:SI ("_ctype_locale_buf") <var_decl
>>> 0x2aaaab15d558 _ctype_locale_buf>)
>>> (const_int 32 [0x20])))
>>>
>>> Any idea why the compiler tries to store such a weird construct? Is it
>>> weird actually, or normal? I am trying to figure out if I either
>>> allowed too much at some point (predicates?) or too little (do I need
>>> to handle this with instructions?)?
>>
>> This seems normal enough to me. It's basically
>> move reg356, $_ctype_locale_buf+32
>> Here _ctype_locale_buf+32 is an immediate value which is known at link
>> time.
>>
>> You will get this kind of thing from code like
>> p = &_ctype_locale_buf[32];
>> if _ctype_locale_buf is a char array.
>>
>> Ian
