On Thu, Dec 17, 2015 at 1:21 PM, Uros Bizjak <ubiz...@gmail.com> wrote:
> On Thu, Dec 17, 2015 at 7:09 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>> On Thu, Dec 17, 2015 at 8:11 AM, H.J. Lu <hjl.to...@gmail.com> wrote:
>>> On Thu, Dec 17, 2015 at 7:50 AM, H.J. Lu <hjl.to...@gmail.com> wrote:
>>>> On Thu, Dec 17, 2015 at 5:42 AM, Uros Bizjak <ubiz...@gmail.com> wrote:
>>>>> On Thu, Dec 17, 2015 at 2:00 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>>>>>> On Thu, Dec 17, 2015 at 2:04 AM, Uros Bizjak <ubiz...@gmail.com> wrote:
>>>>>>> On Thu, Dec 17, 2015 at 12:29 AM, H.J. Lu <hongjiu...@intel.com> wrote:
>>>>>>>> Since sibcall never returns, we can only use call-clobbered register
>>>>>>>> as GOT base. Otherwise, callee-saved register used as GOT base won't
>>>>>>>> be properly restored.
>>>>>>>>
>>>>>>>> Tested on x86-64 with -m32. OK for trunk?
>>>>>>>
>>>>>>> You don't have to add explicit clobber for members of "CLOBBERED_REGS"
>>>>>>> class, and register_no_elim_operand predicate should be used with "U"
>>>>>>> constraint. Also, please introduce new predicate, similar to how
>>>>>>> GOT_memory_operand is defined and handled.
>>>>>>>
>>>>>>
>>>>>> Here is the updated patch. There is a predicate already,
>>>>>> sibcall_memory_operand. It allows any registers to
>>>>>> be as GOT base, which is the root of our problem.
>>>>>> This patch removes GOT slot from it and handles
>>>>>> sibcall over GOT slot with *sibcall_GOT_32 and
>>>>>> *sibcall_value_GOT_32 patterns. Since I need to
>>>>>> expose constraints on GOT base register to RA,
>>>>>> I have to use 2 operands, GOT base and function
>>>>>> symbol, to describe sibcall over 32-bit GOT slot.
>>>>>
>>>>> Please use
>>>>>
>>>>> (mem:SI (plus:SI
>>>>> (match_operand:SI 0 "register_no_elim_operand" "U")
>>>>> (match_operand:SI 1 "GOT32_symbol_operand")))
>>>>> ...
>>>>>
>>>>> to avoid manual rebuild of the operand.
>>>>>
>>>>
>>>> Is this OK?
>>>>
>>>
>>> An updated patch to allow sibcall_memory_operand for RTL
>>> expansion. OK for trunk if there is no regression?
>>>
>>
>> There is no regressions on x86-64 with -m32. OK for trunk?
>
> OK for mainline, with a following change:
>
> @@ -597,11 +597,17 @@
> (match_operand 0 "memory_operand"))))
>
> ;; Return true if OP is a memory operands that can be used in sibcalls.
> +;; Since sibcall never returns, we can only use call-clobbered register
> +;; as GOT base. Allow GOT slot here only with pseudo register as GOT
> +;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
> +;; and *sibcall_value_GOT_32 patterns.
> (define_predicate "sibcall_memory_operand"
> (and (match_operand 0 "memory_operand")
> (match_test "CONSTANT_P (XEXP (op, 0))
> || (GET_CODE (XEXP (op, 0)) == PLUS
> && REG_P (XEXP (XEXP (op, 0), 0))
> + && (REGNO (XEXP (XEXP (op, 0), 0))
> + >= FIRST_PSEUDO_REGISTER)
> && GET_CODE (XEXP (XEXP (op, 0), 1)) == CONST
> && GET_CODE (XEXP (XEXP (XEXP (op, 0), 1), 0)) == UNSPEC
> && XINT (XEXP (XEXP (XEXP (op, 0), 1), 0), 1) == UNSPEC_GOT)")))
>
> You can use (!HARD_REGISTER_NUM_P (...) || call_used_regs[...]) here.
> Call-used hard regs are still allowed here.
>
> Can you please also rewrite this horrible match_test as a block of C
> code using GOT32_symbol_operand predicate?
>
I am retesting the patch with
;; Return true if OP is a memory operands that can be used in sibcalls.
;; Since sibcall never returns, we can only use call-clobbered register
;; as GOT base. Allow GOT slot here only with pseudo register as GOT
;; base. Properly handle sibcall over GOT slot with *sibcall_GOT_32
;; and *sibcall_value_GOT_32 patterns.
(define_predicate "sibcall_memory_operand"
(match_operand 0 "memory_operand")
{
op = XEXP (op, 0);
if (CONSTANT_P (op))
return true;
if (GET_CODE (op) == PLUS && REG_P (XEXP (op, 0)))
{
int regno = REGNO (XEXP (op, 0));
if (!HARD_REGISTER_NUM_P (regno) || call_used_regs[regno])
{
op = XEXP (op, 1);
if (GOT32_symbol_operand (op, VOIDmode))
return true;
}
}
return false;
})
I will check it in if there is no regression.
Thanks.
--
H.J.
