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

[Aaron Watry]

>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.

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.

--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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>