On Mon, Mar 19, 2012 at 8:54 AM, H.J. Lu <hjl.to...@gmail.com> wrote:
> On Mon, Mar 19, 2012 at 8:51 AM, H.J. Lu <hjl.to...@gmail.com> wrote:
>> On Sun, Mar 18, 2012 at 1:55 PM, Uros Bizjak <ubiz...@gmail.com> wrote:
>>> On Sun, Mar 18, 2012 at 5:01 PM, Uros Bizjak <ubiz...@gmail.com> wrote:
>>>
>>>>> I am testing this patch. OK for trunk if it passes all tests?
>>>>
>>>> No, force_reg will generate a pseudo, so this conversion is valid only
>>>> for !can_create_pseudo ().
>>>>
>>>> At least for *tls_initial_exec_x32_store, you will need a temporary to
>>>> split the pattern after reload.
>>
>> Here is the updated patch to add can_create_pseudo. I also changed
>> tls_initial_exec_x32 to take an input register operand as thread pointer.
>>
>>> Please try attached patch. It simply throws away all recent
>>> complications w.r.t. to thread pointer and always handles TP in
>>> DImode.
>>>
>>> The testcase:
>>>
>>> --cut here--
>>> __thread int foo __attribute__ ((tls_model ("initial-exec")));
>>>
>>> void bar (int x)
>>> {
>>> foo = x;
>>> }
>>>
>>> int baz (void)
>>> {
>>> return foo;
>>> }
>>> --cut here--
>>>
>>> Now compiles to:
>>>
>>> bar:
>>> movq foo@gottpoff(%rip), %rax
>>> movl %edi, %fs:(%rax)
>>> ret
>>>
>>> baz:
>>> movq foo@gottpoff(%rip), %rax
>>> movl %fs:(%rax), %eax
>>> ret
>>>
>>> In effect, this always generates %fs(%rDI) and emits REX prefix before
>>> mov/add to satisfy brain-dead linkers.
>>>
>>> The patch is bootstrapping now on x86_64-pc-linux-gnu.
>>>
>>
>> For
>>
>> --
>> extern __thread char c;
>> extern char y;
>> void
>> ie (void)
>> {
>> y = c;
>> }
>> --
>>
>> Your patch generates:
>>
>> movl %fs:0, %eax
>> movq c@gottpoff(%rip), %rdx
>> movzbl (%rax,%rdx), %edx
>> movb %dl, y(%rip)
>> ret
>>
>> It can be optimized to:
>>
>> movq c@gottpoff(%rip), %rax
>> movzbl %fs:(%rax), %eax
>> movb %al, y(%rip)
>> ret
>>
>
> Combine failed:
>
> (set (reg:QI 63 [ c ])
> (mem/c:QI (plus:DI (zero_extend:DI (unspec:SI [
> (const_int 0 [0])
> ] UNSPEC_TP))
> (mem/u/c:DI (const:DI (unspec:DI [
> (symbol_ref:SI ("c") [flags 0x60]
> <var_decl 0x7ffff19b8140 c>)
> ] UNSPEC_GOTNTPOFF)) [2 S8 A8])) [0 c+0 S1 A8]))
>
>
Wrong testcase. IT should be
--
extern __thread char c;
extern __thread short w;
extern char y;
extern short i;
void
ie (void)
{
y = c;
i = w;
}
---
I got
movl %fs:0, %eax
movq c@gottpoff(%rip), %rdx
movzbl (%rax,%rdx), %edx
movb %dl, y(%rip)
movq w@gottpoff(%rip), %rdx
movzwl (%rax,%rdx), %eax
movw %ax, i(%rip)
ret
It can be
movq c@gottpoff(%rip), %rax
movzbl %fs:(%rax), %eax
movb %al, y(%rip)
movq w@gottpoff(%rip), %rax
movzwl %fs:(%rax), %eax
movw %ax, i(%rip)
ret
--
H.J.
