On Wed, Apr 13, 2011 at 5:32 PM, Ian Lance Taylor <i...@google.com> wrote:
> Feng LI <nemoking...@gmail.com> writes:
>
>> I use unspec_volatile for a function with void arguments and
>> void return value for some initialization work. But it didn't generate
>> code in this case. I think probably I need to add more restrictions
>> some where but I don't know why and how. The code looks like:
>>
>> extern __inline void __attribute__((__gnu_inline__, __always_inline__,
>> __artificial__))
>> __TEnd (void)
>> {
>> __builtin_ia32_tend ();
>> }
>>
>> (define_expand "dta_tend"
>> [(unspec_volatile [(const_int 0)] UNSPEC_TEND)]
>> ""
>> "")
>>
>> (define_insn "*dta_tend"
>> [(unspec_volatile [(const_int 0)] UNSPEC_TEND)]
>> ""
>> "tend"
>> [(set_attr "length" "3")
>> (set_attr "mode" "none")])
>
> In the RTL dumps generated by -da, where does the insn appear and where
> does it disappear?
It seems that it disappear at the ffork.c.143r.expand at the very beginning.
I suppose there should be some thing like
(call_insn ....) generated for __builtin_ia32_tend (); But there isn't.
instead, it generated:
;; Generating RTL for gimple basic block 2
;; __builtin_ia32_tend ();
(nil)
Feng
>
> Ian
>
