[Libclc-dev] [PATCH 1/2] atomic: Add generic bitcode implementation of atomic_max

[Aaron Watry]

On Mon, Sep 8, 2014 at 12:12 PM, Matt Arsenault <arsenm2 at gmail.com> wrote:
>
> On Sep 8, 2014, at 12:52 PM, Aaron Watry <awatry at gmail.com> wrote:
>
>> From CL v1.2, Section 6.12.11:
>> int atomic_max (volatile __global int *p, int val)
>> unsigned int atomic_max (volatile __global unsigned int *p, unsigned int val)
>> int atomic_max (volatile __local int *p, int val)
>> unsigned int atomic_max (volatile __local unsigned int *p, unsigned int val)
>>
>> I'm assuming that the pointer declaration as volatile should translate
>> directly to the statement in the bitcode.  Let me know if you think I
>> mis-understood that.  If that's the case, then we also need to fix the
>> atomic_add and atomic_sub functions.
>
> Yes, that’s how I would interpret it.
>>
>> And yes, there's a note that the atom_* functions from CL 1.0 are
>> still supported. Those functions do NOT define the pointers as
>> volatile.
>
> Yes, the sets of atomic functions are separate. It looks like currently atom_add is defined to be the same as atomic_add
>

I'd tend to agree with that statement.

Do you want any changes to this patch, or are we good?

I'm currently trying to get atomic_max done because cppamp-driver-ng
requires it, but eventually I'll probably get around to adding the
other missing atomic_* functions and then the wrappers from CL1.0
atom_* functions.

--Aaron

>
>
>>
>> --Aaron
>>
>> --Aaron
>>
>>
>> On Mon, Sep 8, 2014 at 11:41 AM, Matt Arsenault <arsenm2 at gmail.com> wrote:
>>>
>>> On Sep 8, 2014, at 12:31 PM, Aaron Watry <awatry at gmail.com> wrote:
>>>
>>>> Not used yet...
>>>>
>>>> Signed-off-by: Aaron Watry <awatry at gmail.com>
>>>> ---
>>>> generic/include/clc/atomic/atomic_max.h |  3 +++
>>>> generic/include/clc/clc.h               |  1 +
>>>> generic/lib/atomic/atomic_impl.ll       | 12 ++++++++++++
>>>> 3 files changed, 16 insertions(+)
>>>> create mode 100644 generic/include/clc/atomic/atomic_max.h
>>>>
>>>> diff --git a/generic/include/clc/atomic/atomic_max.h b/generic/include/clc/atomic/atomic_max.h
>>>> new file mode 100644
>>>> index 0000000..30dc180
>>>> --- /dev/null
>>>> +++ b/generic/include/clc/atomic/atomic_max.h
>>>> @@ -0,0 +1,3 @@
>>>> +#define __CLC_FUNCTION atomic_max
>>>> +#include <clc/atomic/atomic_decl.inc>
>>>> +#undef __CLC_FUNCTION
>>>> diff --git a/generic/include/clc/clc.h b/generic/include/clc/clc.h
>>>> index b8c1cb9..b492c54 100644
>>>> --- a/generic/include/clc/clc.h
>>>> +++ b/generic/include/clc/clc.h
>>>> @@ -143,6 +143,7 @@
>>>> #include <clc/atomic/atomic_add.h>
>>>> #include <clc/atomic/atomic_dec.h>
>>>> #include <clc/atomic/atomic_inc.h>
>>>> +#include <clc/atomic/atomic_max.h>
>>>> #include <clc/atomic/atomic_sub.h>
>>>>
>>>> /* cl_khr_global_int32_base_atomics Extension Functions */
>>>> diff --git a/generic/lib/atomic/atomic_impl.ll b/generic/lib/atomic/atomic_impl.ll
>>>> index 9df5b9f..4e228e8 100644
>>>> --- a/generic/lib/atomic/atomic_impl.ll
>>>> +++ b/generic/lib/atomic/atomic_impl.ll
>>>> @@ -10,6 +10,18 @@ entry:
>>>>  ret i32 %0
>>>> }
>>>>
>>>> +define i32 @__clc_atomic_max_addr1(i32 addrspace(1)* nocapture %ptr, i32 %value) nounwind alwaysinline {
>>>> +entry:
>>>> +  %0 = atomicrmw volatile max i32 addrspace(1)* %ptr, i32 %value seq_cst
>>>> +  ret i32 %0
>>>> +}
>>>
>>> Why is it necessary to mark these with volatile (though I never remember whether it’s the atom_* or atomic_* functions which is supposed to be volatile)
>>>
>>>
>>>> +
>>>> +define i32 @__clc_atomic_max_addr3(i32 addrspace(3)* nocapture %ptr, i32 %value) nounwind alwaysinline {
>>>> +entry:
>>>> +  %0 = atomicrmw volatile max i32 addrspace(3)* %ptr, i32 %value seq_cst
>>>> +  ret i32 %0
>>>> +}
>>>> +
>>>> define i32 @__clc_atomic_sub_addr1(i32 addrspace(1)* nocapture %ptr, i32 %value) nounwind alwaysinline {
>>>> entry:
>>>>  %0 = atomicrmw volatile sub i32 addrspace(1)* %ptr, i32 %value seq_cst
>>>> --
>>>> 1.9.1
>>>>
>>>>
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>>>
>