[PATCH] PR target/66232: -fPIC -fno-plt -mx32 fails to generate indirect branch via GOT

[H.J. Lu]

On Thu, May 21, 2015 at 6:11 AM, Uros Bizjak <ubizjak@gmail.com> wrote:
> On Thu, May 21, 2015 at 2:59 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> X32 doesn't support indirect branch via 32-bit memory slot since
>> indirect branch will load 64-bit address from 64-bit memory slot.
>> Since x32 GOT slot is 64-bit, we should allow indirect branch via GOT
>> slot for x32.
>>
>> I am testing it on x32.  OK for master if there is no regression?
>>
>> Thanks.
>>
>>
>> H.J.
>> --
>> gcc/
>>
>>         PR target/66232
>>         * config/i386/constraints.md (Bg): Add a constraint for x32
>>         call and sibcall memory operand.
>>         * config/i386/i386.md (*call_x32): New pattern.
>>         (*sibcall_x32): Likewise.
>>         (*call_value_x32): Likewise.
>>         (*sibcall_value_x32): Likewise.
>>         * config/i386/predicates.md (x32_sibcall_memory_operand): New
>>         predicate.
>>         (x32_call_insn_operand): Likewise.
>>         (x32_sibcall_insn_operand): Likewise.
>>
>> gcc/testsuite/
>>
>>         PR target/66232
>>         * gcc.target/i386/pr66232-1.c: New test.
>>         * gcc.target/i386/pr66232-2.c: Likewise.
>>         * gcc.target/i386/pr66232-3.c: Likewise.
>>         * gcc.target/i386/pr66232-4.c: Likewise.
>
> OK.
>
> maybe you should use match_code some more in x32_sibcall_memory_operand, e.g.
>
> (match_code "constant" "0")
> (match_code "unspec" "00")
>
> But it is up to you, since XINT doesn't fit in this scheme...
>

>>
>> +;; Return true if OP is a memory operand that can be used in x32 calls
>> +;; and sibcalls.  Only th 64-bit GOT slot is allowed.
>> +(define_predicate "x32_sibcall_memory_operand"
>> +  (and (match_operand 0 "memory_operand")
>> +       (match_test "CONSTANT_P (XEXP (op, 0))")
>> +       (match_test "GET_CODE (XEXP (XEXP (op, 0), 0)) == UNSPEC")
>> +       (match_test "XINT (XEXP (XEXP (op, 0), 0), 1) == UNSPEC_GOTPCREL")))
>> +

Since "match_code" doesn't support "constant" neither

#define CONSTANT_P(X)   \
  (GET_RTX_CLASS (GET_CODE (X)) == RTX_CONST_OBJ)

I will keep it asis.

Thanks.

-- 
H.J.