On Wed, Dec 4, 2013 at 9:42 AM, Yufeng Zhang <yufeng.zh...@arm.com> wrote:
> On 12/03/13 21:24, Andrew Pinski wrote:
>>
>> Hi,
>> With ILP32 AARCH64, Pmode (DImode) != ptrmode (SImode) so the variable
>> decl
>> has a mode of SImode while the register is DImode. So the target that
>> gets
>> passed down to expand_builtin_thread_pointer is NULL as expand does not
>> know how to get a subreg for a pointer type.
>>
>> This fixes the problem by handling a NULL target like we are able to
>> handle
>> for a non register/correct mode target inside
>> expand_builtin_thread_pointer.
>>
>> OK? Build and tested for aarch64-elf with no regressions.
>>
>> Thanks,
>> Andrew Pinski
>>
>> * builtins.c (expand_builtin_thread_pointer): Create a new target
>> when the target is NULL.
>> ---
>> gcc/ChangeLog | 5 +++++
>> gcc/builtins.c | 2 +-
>> 2 files changed, 6 insertions(+), 1 deletions(-)
>>
>> diff --git a/gcc/builtins.c b/gcc/builtins.c
>> index 4f1c818..66797fa 100644
>> --- a/gcc/builtins.c
>> +++ b/gcc/builtins.c
>> @@ -5699,7 +5699,7 @@ expand_builtin_thread_pointer (tree exp, rtx target)
>> if (icode != CODE_FOR_nothing)
>> {
>> struct expand_operand op;
>> - if (!REG_P (target) || GET_MODE (target) != Pmode)
>> + if (target == NULL_RTX || !REG_P (target) || GET_MODE (target) !=
>> Pmode)
>> target = gen_reg_rtx (Pmode);
>> create_output_operand (&op, target, Pmode);
>> expand_insn (icode, 1,&op);
>
>
> Shouldn't thread pointer have ptr_mode instead? I'm aware that on AArch64
> the thread pointer system register tpidr_el0 is 64-bit wide regardless of
> ILP32 or not, but in the abstracted view of AArch64 ILP32 world, the thread
> pointer shall be a 32-bit pointer; the OS should have taken care of the
> hardware register tpidr_el0 by having its higher 32 bits cleared. I think
> expand_builtin_thread_pointer and expand_builtin_set_thread_pointer should
> use ptr_mode instead. Correct me if I missed anything.
>
> Add Chung-Lin Tang to the CC list; Chung-Lin wrote these builtins in r192364
Pmode seems more correct as the hardware mode is Pmode, having it
ptr_mode would expose the C size of the pointer rather than the
hardware size.
Thanks,
Andrew Pinski
>
> Yufeng
>
