[OpenCL] Add pure attributes to vload builtins

[stuart]

Summary

Use the pure attribute for the vload, vload_half and vloada_half builtins.

[svenvh]

For the constant address space, the const attribute (or readnone) can be used. As memory in the constant address space is immutable, the statement in the langref that: "if a readnone function reads or writes memory visible to the program, or has other side-effects, the behavior is undefined" does not apply. The reading of immutable memory does not have side-effects, nor can it be affected by side-effects.

I think readnone might be too strong, because the pointer argument will still be dereferenced (while readnone implies that "the function computes its result [...] based strictly on its arguments, without dereferencing any pointer arguments").

[stuart]

In D110742#3048301, @svenvh wrote:

For the constant address space, the const attribute (or readnone) can be used. As memory in the constant address space is immutable, the statement in the langref that: "if a readnone function reads or writes memory visible to the program, or has other side-effects, the behavior is undefined" does not apply. The reading of immutable memory does not have side-effects, nor can it be affected by side-effects.

I think readnone might be too strong, because the pointer argument will still be dereferenced (while readnone implies that "the function computes its result [...] based strictly on its arguments, without dereferencing any pointer arguments").

That may be so, but the function does not have its own side-effects, nor can it depend upon any side-effects, as the memory in question is truly immutable (i.e. it cannot even be changed by another process, thread, or shared memory interface in such a way that would be observable).

All functions, with or without __attribute__((const)) can be said to require memory reads in the form of the instruction fetches needed to execute the instructions that comprise the compiled function. It is also quite normal for constant pools to be generated for a function, from which memory reads will be performed despite no pointer being dereferenced in the original C source.

Both __attribute__((const)) and readnone are intended to permit arbitrary code motion, and so in my opinion the langref misstates the true nature of the readnone attribute. (The Clang manual does not even document __attribute__((const)).) From a cursory examination of the LLVM source, I did not find any use of readnone that conflicts with this interpretation of the readnone attribute.

Does the langref need to be amended, first, or is it okay to interpret the readnone attribute as it was clearly intended, without going through the process of updating the langref first?

I can update this review to use __attribute__((pure)) for all address spaces, for the time being, but it seems a shame that the poor wording in the langref might (necessarily) prevent us from making the optimal change.

[svenvh]

Does the langref need to be amended, first, or is it okay to interpret the readnone attribute as it was clearly intended, without going through the process of updating the langref first?

I can update this review to use __attribute__((pure)) for all address spaces, for the time being, but it seems a shame that the poor wording in the langref might (necessarily) prevent us from making the optimal change.

Apologies for the late reply... I'd prefer to get the langref updated first, for the sake of consistency and to ensure other stakeholders agree with the interpretation. You can still go ahead with the __attribute__((pure)) changes of course.

[stuart]

In D110742#3194608, @svenvh wrote:

Apologies for the late reply... I'd prefer to get the langref updated first, for the sake of consistency and to ensure other stakeholders agree with the interpretation. You can still go ahead with the __attribute__((pure)) changes of course.

Thanks! I have updated the review to use __attribute__((pure)) only (i.e. it no longer uses __attribute__((const)).

[svenvh]

In D110742#3197183, @stuart wrote:

Thanks! I have updated the review to use __attribute__((pure)) only (i.e. it no longer uses __attribute__((const)).

LGTM!

[thakis]

looks like this broke tests: http://45.33.8.238/linux/63308/step_7.txt

Please take a look, and revert for now if it takes a while to fix.

[stuart]

I've updated the review to include test changes that are required for check-clang-semaopencl to pass.

[thakis]

Thanks! Bots look happy again :)

clang/lib/Headers/opencl-c.h

  *
  * The address computed as (p + (offset * n)) must be
  * 8-bit aligned if gentype is char, uchar;
  * 16-bit aligned if gentype is short, ushort, half;
  * 32-bit aligned if gentype is int, uint, float;
  * 64-bit aligned if gentype is long, ulong, double.
  */
 
-char2 __ovld vload2(size_t offset, const __constant char *p);
-uchar2 __ovld vload2(size_t offset, const __constant uchar *p);
-short2 __ovld vload2(size_t offset, const __constant short *p);
-ushort2 __ovld vload2(size_t offset, const __constant ushort *p);
-int2 __ovld vload2(size_t offset, const __constant int *p);
-uint2 __ovld vload2(size_t offset, const __constant uint *p);
-long2 __ovld vload2(size_t offset, const __constant long *p);
-ulong2 __ovld vload2(size_t offset, const __constant ulong *p);
-float2 __ovld vload2(size_t offset, const __constant float *p);
-char3 __ovld vload3(size_t offset, const __constant char *p);
-uchar3 __ovld vload3(size_t offset, const __constant uchar *p);
-short3 __ovld vload3(size_t offset, const __constant short *p);
-ushort3 __ovld vload3(size_t offset, const __constant ushort *p);
-int3 __ovld vload3(size_t offset, const __constant int *p);
-uint3 __ovld vload3(size_t offset, const __constant uint *p);
-long3 __ovld vload3(size_t offset, const __constant long *p);
-ulong3 __ovld vload3(size_t offset, const __constant ulong *p);
-float3 __ovld vload3(size_t offset, const __constant float *p);
-char4 __ovld vload4(size_t offset, const __constant char *p);
-uchar4 __ovld vload4(size_t offset, const __constant uchar *p);
-short4 __ovld vload4(size_t offset, const __constant short *p);
-ushort4 __ovld vload4(size_t offset, const __constant ushort *p);
-int4 __ovld vload4(size_t offset, const __constant int *p);
-uint4 __ovld vload4(size_t offset, const __constant uint *p);
-long4 __ovld vload4(size_t offset, const __constant long *p);
-ulong4 __ovld vload4(size_t offset, const __constant ulong *p);
-float4 __ovld vload4(size_t offset, const __constant float *p);
-char8 __ovld vload8(size_t offset, const __constant char *p);
-uchar8 __ovld vload8(size_t offset, const __constant uchar *p);
-short8 __ovld vload8(size_t offset, const __constant short *p);
-ushort8 __ovld vload8(size_t offset, const __constant ushort *p);
-int8 __ovld vload8(size_t offset, const __constant int *p);
-uint8 __ovld vload8(size_t offset, const __constant uint *p);
-long8 __ovld vload8(size_t offset, const __constant long *p);
-ulong8 __ovld vload8(size_t offset, const __constant ulong *p);
-float8 __ovld vload8(size_t offset, const __constant float *p);
-char16 __ovld vload16(size_t offset, const __constant char *p);
-uchar16 __ovld vload16(size_t offset, const __constant uchar *p);
-short16 __ovld vload16(size_t offset, const __constant short *p);
-ushort16 __ovld vload16(size_t offset, const __constant ushort *p);
-int16 __ovld vload16(size_t offset, const __constant int *p);
-uint16 __ovld vload16(size_t offset, const __constant uint *p);
-long16 __ovld vload16(size_t offset, const __constant long *p);
-ulong16 __ovld vload16(size_t offset, const __constant ulong *p);
-float16 __ovld vload16(size_t offset, const __constant float *p);
-#ifdef cl_khr_fp64
-double2 __ovld vload2(size_t offset, const __constant double *p);
-double3 __ovld vload3(size_t offset, const __constant double *p);
-double4 __ovld vload4(size_t offset, const __constant double *p);
-double8 __ovld vload8(size_t offset, const __constant double *p);
-double16 __ovld vload16(size_t offset, const __constant double *p);
+char2 __ovld __purefn vload2(size_t offset, const __constant char *p);
+uchar2 __ovld __purefn vload2(size_t offset, const __constant uchar *p);
+short2 __ovld __purefn vload2(size_t offset, const __constant short *p);
+ushort2 __ovld __purefn vload2(size_t offset, const __constant ushort *p);
+int2 __ovld __purefn vload2(size_t offset, const __constant int *p);
+uint2 __ovld __purefn vload2(size_t offset, const __constant uint *p);
+long2 __ovld __purefn vload2(size_t offset, const __constant long *p);
+ulong2 __ovld __purefn vload2(size_t offset, const __constant ulong *p);
+float2 __ovld __purefn vload2(size_t offset, const __constant float *p);
+char3 __ovld __purefn vload3(size_t offset, const __constant char *p);
+uchar3 __ovld __purefn vload3(size_t offset, const __constant uchar *p);
+short3 __ovld __purefn vload3(size_t offset, const __constant short *p);
+ushort3 __ovld __purefn vload3(size_t offset, const __constant ushort *p);
+int3 __ovld __purefn vload3(size_t offset, const __constant int *p);
+uint3 __ovld __purefn vload3(size_t offset, const __constant uint *p);
+long3 __ovld __purefn vload3(size_t offset, const __constant long *p);
+ulong3 __ovld __purefn vload3(size_t offset, const __constant ulong *p);
+float3 __ovld __purefn vload3(size_t offset, const __constant float *p);
+char4 __ovld __purefn vload4(size_t offset, const __constant char *p);
+uchar4 __ovld __purefn vload4(size_t offset, const __constant uchar *p);
+short4 __ovld __purefn vload4(size_t offset, const __constant short *p);
+ushort4 __ovld __purefn vload4(size_t offset, const __constant ushort *p);
+int4 __ovld __purefn vload4(size_t offset, const __constant int *p);
+uint4 __ovld __purefn vload4(size_t offset, const __constant uint *p);
+long4 __ovld __purefn vload4(size_t offset, const __constant long *p);
+ulong4 __ovld __purefn vload4(size_t offset, const __constant ulong *p);
+float4 __ovld __purefn vload4(size_t offset, const __constant float *p);
+char8 __ovld __purefn vload8(size_t offset, const __constant char *p);
+uchar8 __ovld __purefn vload8(size_t offset, const __constant uchar *p);
+short8 __ovld __purefn vload8(size_t offset, const __constant short *p);
+ushort8 __ovld __purefn vload8(size_t offset, const __constant ushort *p);
+int8 __ovld __purefn vload8(size_t offset, const __constant int *p);
+uint8 __ovld __purefn vload8(size_t offset, const __constant uint *p);
+long8 __ovld __purefn vload8(size_t offset, const __constant long *p);
+ulong8 __ovld __purefn vload8(size_t offset, const __constant ulong *p);
+float8 __ovld __purefn vload8(size_t offset, const __constant float *p);
+char16 __ovld __purefn vload16(size_t offset, const __constant char *p);
+uchar16 __ovld __purefn vload16(size_t offset, const __constant uchar *p);
+short16 __ovld __purefn vload16(size_t offset, const __constant short *p);
+ushort16 __ovld __purefn vload16(size_t offset, const __constant ushort *p);
+int16 __ovld __purefn vload16(size_t offset, const __constant int *p);
+uint16 __ovld __purefn vload16(size_t offset, const __constant uint *p);
+long16 __ovld __purefn vload16(size_t offset, const __constant long *p);
+ulong16 __ovld __purefn vload16(size_t offset, const __constant ulong *p);
+float16 __ovld __purefn vload16(size_t offset, const __constant float *p);
+#ifdef cl_khr_fp64
+double2 __ovld __purefn vload2(size_t offset, const __constant double *p);
+double3 __ovld __purefn vload3(size_t offset, const __constant double *p);
+double4 __ovld __purefn vload4(size_t offset, const __constant double *p);
+double8 __ovld __purefn vload8(size_t offset, const __constant double *p);
+double16 __ovld __purefn vload16(size_t offset, const __constant double *p);
 #endif //cl_khr_fp64
 
 #ifdef cl_khr_fp16
-half __ovld vload(size_t offset, const __constant half *p);
-half2 __ovld vload2(size_t offset, const __constant half *p);
-half3 __ovld vload3(size_t offset, const __constant half *p);
-half4 __ovld vload4(size_t offset, const __constant half *p);
-half8 __ovld vload8(size_t offset, const __constant half *p);
-half16 __ovld vload16(size_t offset, const __constant half *p);
+half __ovld __purefn vload(size_t offset, const __constant half *p);
+half2 __ovld __purefn vload2(size_t offset, const __constant half *p);
+half3 __ovld __purefn vload3(size_t offset, const __constant half *p);
+half4 __ovld __purefn vload4(size_t offset, const __constant half *p);
+half8 __ovld __purefn vload8(size_t offset, const __constant half *p);
+half16 __ovld __purefn vload16(size_t offset, const __constant half *p);
 #endif //cl_khr_fp16
 
 #if defined(__opencl_c_generic_address_space)
-char2 __ovld vload2(size_t offset, const char *p);
-uchar2 __ovld vload2(size_t offset, const uchar *p);
-short2 __ovld vload2(size_t offset, const short *p);
-ushort2 __ovld vload2(size_t offset, const ushort *p);
-int2 __ovld vload2(size_t offset, const int *p);
-uint2 __ovld vload2(size_t offset, const uint *p);
-long2 __ovld vload2(size_t offset, const long *p);
-ulong2 __ovld vload2(size_t offset, const ulong *p);
-float2 __ovld vload2(size_t offset, const float *p);
-char3 __ovld vload3(size_t offset, const char *p);
-uchar3 __ovld vload3(size_t offset, const uchar *p);
-short3 __ovld vload3(size_t offset, const short *p);
-ushort3 __ovld vload3(size_t offset, const ushort *p);
-int3 __ovld vload3(size_t offset, const int *p);
-uint3 __ovld vload3(size_t offset, const uint *p);
-long3 __ovld vload3(size_t offset, const long *p);
-ulong3 __ovld vload3(size_t offset, const ulong *p);
-float3 __ovld vload3(size_t offset, const float *p);
-char4 __ovld vload4(size_t offset, const char *p);
-uchar4 __ovld vload4(size_t offset, const uchar *p);
-short4 __ovld vload4(size_t offset, const short *p);
-ushort4 __ovld vload4(size_t offset, const ushort *p);
-int4 __ovld vload4(size_t offset, const int *p);
-uint4 __ovld vload4(size_t offset, const uint *p);
-long4 __ovld vload4(size_t offset, const long *p);
-ulong4 __ovld vload4(size_t offset, const ulong *p);
-float4 __ovld vload4(size_t offset, const float *p);
-char8 __ovld vload8(size_t offset, const char *p);
-uchar8 __ovld vload8(size_t offset, const uchar *p);
-short8 __ovld vload8(size_t offset, const short *p);
-ushort8 __ovld vload8(size_t offset, const ushort *p);
-int8 __ovld vload8(size_t offset, const int *p);
-uint8 __ovld vload8(size_t offset, const uint *p);
-long8 __ovld vload8(size_t offset, const long *p);
-ulong8 __ovld vload8(size_t offset, const ulong *p);
-float8 __ovld vload8(size_t offset, const float *p);
-char16 __ovld vload16(size_t offset, const char *p);
-uchar16 __ovld vload16(size_t offset, const uchar *p);
-short16 __ovld vload16(size_t offset, const short *p);
-ushort16 __ovld vload16(size_t offset, const ushort *p);
-int16 __ovld vload16(size_t offset, const int *p);
-uint16 __ovld vload16(size_t offset, const uint *p);
-long16 __ovld vload16(size_t offset, const long *p);
-ulong16 __ovld vload16(size_t offset, const ulong *p);
-float16 __ovld vload16(size_t offset, const float *p);
-
-#ifdef cl_khr_fp64
-double2 __ovld vload2(size_t offset, const double *p);
-double3 __ovld vload3(size_t offset, const double *p);
-double4 __ovld vload4(size_t offset, const double *p);
-double8 __ovld vload8(size_t offset, const double *p);
-double16 __ovld vload16(size_t offset, const double *p);
+char2 __ovld __purefn vload2(size_t offset, const char *p);
+uchar2 __ovld __purefn vload2(size_t offset, const uchar *p);
+short2 __ovld __purefn vload2(size_t offset, const short *p);
+ushort2 __ovld __purefn vload2(size_t offset, const ushort *p);
+int2 __ovld __purefn vload2(size_t offset, const int *p);
+uint2 __ovld __purefn vload2(size_t offset, const uint *p);
+long2 __ovld __purefn vload2(size_t offset, const long *p);
+ulong2 __ovld __purefn vload2(size_t offset, const ulong *p);
+float2 __ovld __purefn vload2(size_t offset, const float *p);
+char3 __ovld __purefn vload3(size_t offset, const char *p);
+uchar3 __ovld __purefn vload3(size_t offset, const uchar *p);
+short3 __ovld __purefn vload3(size_t offset, const short *p);
+ushort3 __ovld __purefn vload3(size_t offset, const ushort *p);
+int3 __ovld __purefn vload3(size_t offset, const int *p);
+uint3 __ovld __purefn vload3(size_t offset, const uint *p);
+long3 __ovld __purefn vload3(size_t offset, const long *p);
+ulong3 __ovld __purefn vload3(size_t offset, const ulong *p);
+float3 __ovld __purefn vload3(size_t offset, const float *p);
+char4 __ovld __purefn vload4(size_t offset, const char *p);
+uchar4 __ovld __purefn vload4(size_t offset, const uchar *p);
+short4 __ovld __purefn vload4(size_t offset, const short *p);
+ushort4 __ovld __purefn vload4(size_t offset, const ushort *p);
+int4 __ovld __purefn vload4(size_t offset, const int *p);
+uint4 __ovld __purefn vload4(size_t offset, const uint *p);
+long4 __ovld __purefn vload4(size_t offset, const long *p);
+ulong4 __ovld __purefn vload4(size_t offset, const ulong *p);
+float4 __ovld __purefn vload4(size_t offset, const float *p);
+char8 __ovld __purefn vload8(size_t offset, const char *p);
+uchar8 __ovld __purefn vload8(size_t offset, const uchar *p);
+short8 __ovld __purefn vload8(size_t offset, const short *p);
+ushort8 __ovld __purefn vload8(size_t offset, const ushort *p);
+int8 __ovld __purefn vload8(size_t offset, const int *p);
+uint8 __ovld __purefn vload8(size_t offset, const uint *p);
+long8 __ovld __purefn vload8(size_t offset, const long *p);
+ulong8 __ovld __purefn vload8(size_t offset, const ulong *p);
+float8 __ovld __purefn vload8(size_t offset, const float *p);
+char16 __ovld __purefn vload16(size_t offset, const char *p);
+uchar16 __ovld __purefn vload16(size_t offset, const uchar *p);
+short16 __ovld __purefn vload16(size_t offset, const short *p);
+ushort16 __ovld __purefn vload16(size_t offset, const ushort *p);
+int16 __ovld __purefn vload16(size_t offset, const int *p);
+uint16 __ovld __purefn vload16(size_t offset, const uint *p);
+long16 __ovld __purefn vload16(size_t offset, const long *p);
+ulong16 __ovld __purefn vload16(size_t offset, const ulong *p);
+float16 __ovld __purefn vload16(size_t offset, const float *p);
+
+#ifdef cl_khr_fp64
+double2 __ovld __purefn vload2(size_t offset, const double *p);
+double3 __ovld __purefn vload3(size_t offset, const double *p);
+double4 __ovld __purefn vload4(size_t offset, const double *p);
+double8 __ovld __purefn vload8(size_t offset, const double *p);
+double16 __ovld __purefn vload16(size_t offset, const double *p);
 #endif //cl_khr_fp64
 
 #ifdef cl_khr_fp16
-half __ovld vload(size_t offset, const half *p);
-half2 __ovld vload2(size_t offset, const half *p);
-half3 __ovld vload3(size_t offset, const half *p);
-half4 __ovld vload4(size_t offset, const half *p);
-half8 __ovld vload8(size_t offset, const half *p);
-half16 __ovld vload16(size_t offset, const half *p);
+half __ovld __purefn vload(size_t offset, const half *p);
+half2 __ovld __purefn vload2(size_t offset, const half *p);
+half3 __ovld __purefn vload3(size_t offset, const half *p);
+half4 __ovld __purefn vload4(size_t offset, const half *p);
+half8 __ovld __purefn vload8(size_t offset, const half *p);
+half16 __ovld __purefn vload16(size_t offset, const half *p);
 #endif //cl_khr_fp16
 #else
-char2 __ovld vload2(size_t offset, const __global char *p);
-uchar2 __ovld vload2(size_t offset, const __global uchar *p);
-short2 __ovld vload2(size_t offset, const __global short *p);
-ushort2 __ovld vload2(size_t offset, const __global ushort *p);
-int2 __ovld vload2(size_t offset, const __global int *p);
-uint2 __ovld vload2(size_t offset, const __global uint *p);
-long2 __ovld vload2(size_t offset, const __global long *p);
-ulong2 __ovld vload2(size_t offset, const __global ulong *p);
-float2 __ovld vload2(size_t offset, const __global float *p);
-char3 __ovld vload3(size_t offset, const __global char *p);
-uchar3 __ovld vload3(size_t offset, const __global uchar *p);
-short3 __ovld vload3(size_t offset, const __global short *p);
-ushort3 __ovld vload3(size_t offset, const __global ushort *p);
-int3 __ovld vload3(size_t offset, const __global int *p);
-uint3 __ovld vload3(size_t offset, const __global uint *p);
-long3 __ovld vload3(size_t offset, const __global long *p);
-ulong3 __ovld vload3(size_t offset, const __global ulong *p);
-float3 __ovld vload3(size_t offset, const __global float *p);
-char4 __ovld vload4(size_t offset, const __global char *p);
-uchar4 __ovld vload4(size_t offset, const __global uchar *p);
-short4 __ovld vload4(size_t offset, const __global short *p);
-ushort4 __ovld vload4(size_t offset, const __global ushort *p);
-int4 __ovld vload4(size_t offset, const __global int *p);
-uint4 __ovld vload4(size_t offset, const __global uint *p);
-long4 __ovld vload4(size_t offset, const __global long *p);
-ulong4 __ovld vload4(size_t offset, const __global ulong *p);
-float4 __ovld vload4(size_t offset, const __global float *p);
-char8 __ovld vload8(size_t offset, const __global char *p);
-uchar8 __ovld vload8(size_t offset, const __global uchar *p);
-short8 __ovld vload8(size_t offset, const __global short *p);
-ushort8 __ovld vload8(size_t offset, const __global ushort *p);
-int8 __ovld vload8(size_t offset, const __global int *p);
-uint8 __ovld vload8(size_t offset, const __global uint *p);
-long8 __ovld vload8(size_t offset, const __global long *p);
-ulong8 __ovld vload8(size_t offset, const __global ulong *p);
-float8 __ovld vload8(size_t offset, const __global float *p);
-char16 __ovld vload16(size_t offset, const __global char *p);
-uchar16 __ovld vload16(size_t offset, const __global uchar *p);
-short16 __ovld vload16(size_t offset, const __global short *p);
-ushort16 __ovld vload16(size_t offset, const __global ushort *p);
-int16 __ovld vload16(size_t offset, const __global int *p);
-uint16 __ovld vload16(size_t offset, const __global uint *p);
-long16 __ovld vload16(size_t offset, const __global long *p);
-ulong16 __ovld vload16(size_t offset, const __global ulong *p);
-float16 __ovld vload16(size_t offset, const __global float *p);
-char2 __ovld vload2(size_t offset, const __local char *p);
-uchar2 __ovld vload2(size_t offset, const __local uchar *p);
-short2 __ovld vload2(size_t offset, const __local short *p);
-ushort2 __ovld vload2(size_t offset, const __local ushort *p);
-int2 __ovld vload2(size_t offset, const __local int *p);
-uint2 __ovld vload2(size_t offset, const __local uint *p);
-long2 __ovld vload2(size_t offset, const __local long *p);
-ulong2 __ovld vload2(size_t offset, const __local ulong *p);
-float2 __ovld vload2(size_t offset, const __local float *p);
-char3 __ovld vload3(size_t offset, const __local char *p);
-uchar3 __ovld vload3(size_t offset, const __local uchar *p);
-short3 __ovld vload3(size_t offset, const __local short *p);
-ushort3 __ovld vload3(size_t offset, const __local ushort *p);
-int3 __ovld vload3(size_t offset, const __local int *p);
-uint3 __ovld vload3(size_t offset, const __local uint *p);
-long3 __ovld vload3(size_t offset, const __local long *p);
-ulong3 __ovld vload3(size_t offset, const __local ulong *p);
-float3 __ovld vload3(size_t offset, const __local float *p);
-char4 __ovld vload4(size_t offset, const __local char *p);
-uchar4 __ovld vload4(size_t offset, const __local uchar *p);
-short4 __ovld vload4(size_t offset, const __local short *p);
-ushort4 __ovld vload4(size_t offset, const __local ushort *p);
-int4 __ovld vload4(size_t offset, const __local int *p);
-uint4 __ovld vload4(size_t offset, const __local uint *p);
-long4 __ovld vload4(size_t offset, const __local long *p);
-ulong4 __ovld vload4(size_t offset, const __local ulong *p);
-float4 __ovld vload4(size_t offset, const __local float *p);
-char8 __ovld vload8(size_t offset, const __local char *p);
-uchar8 __ovld vload8(size_t offset, const __local uchar *p);
-short8 __ovld vload8(size_t offset, const __local short *p);
-ushort8 __ovld vload8(size_t offset, const __local ushort *p);
-int8 __ovld vload8(size_t offset, const __local int *p);
-uint8 __ovld vload8(size_t offset, const __local uint *p);
-long8 __ovld vload8(size_t offset, const __local long *p);
-ulong8 __ovld vload8(size_t offset, const __local ulong *p);
-float8 __ovld vload8(size_t offset, const __local float *p);
-char16 __ovld vload16(size_t offset, const __local char *p);
-uchar16 __ovld vload16(size_t offset, const __local uchar *p);
-short16 __ovld vload16(size_t offset, const __local short *p);
-ushort16 __ovld vload16(size_t offset, const __local ushort *p);
-int16 __ovld vload16(size_t offset, const __local int *p);
-uint16 __ovld vload16(size_t offset, const __local uint *p);
-long16 __ovld vload16(size_t offset, const __local long *p);
-ulong16 __ovld vload16(size_t offset, const __local ulong *p);
-float16 __ovld vload16(size_t offset, const __local float *p);
-char2 __ovld vload2(size_t offset, const __private char *p);
-uchar2 __ovld vload2(size_t offset, const __private uchar *p);
-short2 __ovld vload2(size_t offset, const __private short *p);
-ushort2 __ovld vload2(size_t offset, const __private ushort *p);
-int2 __ovld vload2(size_t offset, const __private int *p);
-uint2 __ovld vload2(size_t offset, const __private uint *p);
-long2 __ovld vload2(size_t offset, const __private long *p);
-ulong2 __ovld vload2(size_t offset, const __private ulong *p);
-float2 __ovld vload2(size_t offset, const __private float *p);
-char3 __ovld vload3(size_t offset, const __private char *p);
-uchar3 __ovld vload3(size_t offset, const __private uchar *p);
-short3 __ovld vload3(size_t offset, const __private short *p);
-ushort3 __ovld vload3(size_t offset, const __private ushort *p);
-int3 __ovld vload3(size_t offset, const __private int *p);
-uint3 __ovld vload3(size_t offset, const __private uint *p);
-long3 __ovld vload3(size_t offset, const __private long *p);
-ulong3 __ovld vload3(size_t offset, const __private ulong *p);
-float3 __ovld vload3(size_t offset, const __private float *p);
-char4 __ovld vload4(size_t offset, const __private char *p);
-uchar4 __ovld vload4(size_t offset, const __private uchar *p);
-short4 __ovld vload4(size_t offset, const __private short *p);
-ushort4 __ovld vload4(size_t offset, const __private ushort *p);
-int4 __ovld vload4(size_t offset, const __private int *p);
-uint4 __ovld vload4(size_t offset, const __private uint *p);
-long4 __ovld vload4(size_t offset, const __private long *p);
-ulong4 __ovld vload4(size_t offset, const __private ulong *p);
-float4 __ovld vload4(size_t offset, const __private float *p);
-char8 __ovld vload8(size_t offset, const __private char *p);
-uchar8 __ovld vload8(size_t offset, const __private uchar *p);
-short8 __ovld vload8(size_t offset, const __private short *p);
-ushort8 __ovld vload8(size_t offset, const __private ushort *p);
-int8 __ovld vload8(size_t offset, const __private int *p);
-uint8 __ovld vload8(size_t offset, const __private uint *p);
-long8 __ovld vload8(size_t offset, const __private long *p);
-ulong8 __ovld vload8(size_t offset, const __private ulong *p);
-float8 __ovld vload8(size_t offset, const __private float *p);
-char16 __ovld vload16(size_t offset, const __private char *p);
-uchar16 __ovld vload16(size_t offset, const __private uchar *p);
-short16 __ovld vload16(size_t offset, const __private short *p);
-ushort16 __ovld vload16(size_t offset, const __private ushort *p);
-int16 __ovld vload16(size_t offset, const __private int *p);
-uint16 __ovld vload16(size_t offset, const __private uint *p);
-long16 __ovld vload16(size_t offset, const __private long *p);
-ulong16 __ovld vload16(size_t offset, const __private ulong *p);
-float16 __ovld vload16(size_t offset, const __private float *p);
-
-#ifdef cl_khr_fp64
-double2 __ovld vload2(size_t offset, const __global double *p);
-double3 __ovld vload3(size_t offset, const __global double *p);
-double4 __ovld vload4(size_t offset, const __global double *p);
-double8 __ovld vload8(size_t offset, const __global double *p);
-double16 __ovld vload16(size_t offset, const __global double *p);
-double2 __ovld vload2(size_t offset, const __local double *p);
-double3 __ovld vload3(size_t offset, const __local double *p);
-double4 __ovld vload4(size_t offset, const __local double *p);
-double8 __ovld vload8(size_t offset, const __local double *p);
-double16 __ovld vload16(size_t offset, const __local double *p);
-double2 __ovld vload2(size_t offset, const __private double *p);
-double3 __ovld vload3(size_t offset, const __private double *p);
-double4 __ovld vload4(size_t offset, const __private double *p);
-double8 __ovld vload8(size_t offset, const __private double *p);
-double16 __ovld vload16(size_t offset, const __private double *p);
-#endif //cl_khr_fp64
-
-#ifdef cl_khr_fp16
-half __ovld vload(size_t offset, const __global half *p);
-half2 __ovld vload2(size_t offset, const __global half *p);
-half3 __ovld vload3(size_t offset, const __global half *p);
-half4 __ovld vload4(size_t offset, const __global half *p);
-half8 __ovld vload8(size_t offset, const __global half *p);
-half16 __ovld vload16(size_t offset, const __global half *p);
-half __ovld vload(size_t offset, const __local half *p);
-half2 __ovld vload2(size_t offset, const __local half *p);
-half3 __ovld vload3(size_t offset, const __local half *p);
-half4 __ovld vload4(size_t offset, const __local half *p);
-half8 __ovld vload8(size_t offset, const __local half *p);
-half16 __ovld vload16(size_t offset, const __local half *p);
-half __ovld vload(size_t offset, const __private half *p);
-half2 __ovld vload2(size_t offset, const __private half *p);
-half3 __ovld vload3(size_t offset, const __private half *p);
-half4 __ovld vload4(size_t offset, const __private half *p);
-half8 __ovld vload8(size_t offset, const __private half *p);
-half16 __ovld vload16(size_t offset, const __private half *p);
+char2 __ovld __purefn vload2(size_t offset, const __global char *p);
+uchar2 __ovld __purefn vload2(size_t offset, const __global uchar *p);
+short2 __ovld __purefn vload2(size_t offset, const __global short *p);
+ushort2 __ovld __purefn vload2(size_t offset, const __global ushort *p);
+int2 __ovld __purefn vload2(size_t offset, const __global int *p);
+uint2 __ovld __purefn vload2(size_t offset, const __global uint *p);
+long2 __ovld __purefn vload2(size_t offset, const __global long *p);
+ulong2 __ovld __purefn vload2(size_t offset, const __global ulong *p);
+float2 __ovld __purefn vload2(size_t offset, const __global float *p);
+char3 __ovld __purefn vload3(size_t offset, const __global char *p);
+uchar3 __ovld __purefn vload3(size_t offset, const __global uchar *p);
+short3 __ovld __purefn vload3(size_t offset, const __global short *p);
+ushort3 __ovld __purefn vload3(size_t offset, const __global ushort *p);
+int3 __ovld __purefn vload3(size_t offset, const __global int *p);
+uint3 __ovld __purefn vload3(size_t offset, const __global uint *p);
+long3 __ovld __purefn vload3(size_t offset, const __global long *p);
+ulong3 __ovld __purefn vload3(size_t offset, const __global ulong *p);
+float3 __ovld __purefn vload3(size_t offset, const __global float *p);
+char4 __ovld __purefn vload4(size_t offset, const __global char *p);
+uchar4 __ovld __purefn vload4(size_t offset, const __global uchar *p);
+short4 __ovld __purefn vload4(size_t offset, const __global short *p);
+ushort4 __ovld __purefn vload4(size_t offset, const __global ushort *p);
+int4 __ovld __purefn vload4(size_t offset, const __global int *p);
+uint4 __ovld __purefn vload4(size_t offset, const __global uint *p);
+long4 __ovld __purefn vload4(size_t offset, const __global long *p);
+ulong4 __ovld __purefn vload4(size_t offset, const __global ulong *p);
+float4 __ovld __purefn vload4(size_t offset, const __global float *p);
+char8 __ovld __purefn vload8(size_t offset, const __global char *p);
+uchar8 __ovld __purefn vload8(size_t offset, const __global uchar *p);
+short8 __ovld __purefn vload8(size_t offset, const __global short *p);
+ushort8 __ovld __purefn vload8(size_t offset, const __global ushort *p);
+int8 __ovld __purefn vload8(size_t offset, const __global int *p);
+uint8 __ovld __purefn vload8(size_t offset, const __global uint *p);
+long8 __ovld __purefn vload8(size_t offset, const __global long *p);
+ulong8 __ovld __purefn vload8(size_t offset, const __global ulong *p);
+float8 __ovld __purefn vload8(size_t offset, const __global float *p);
+char16 __ovld __purefn vload16(size_t offset, const __global char *p);
+uchar16 __ovld __purefn vload16(size_t offset, const __global uchar *p);
+short16 __ovld __purefn vload16(size_t offset, const __global short *p);
+ushort16 __ovld __purefn vload16(size_t offset, const __global ushort *p);
+int16 __ovld __purefn vload16(size_t offset, const __global int *p);
+uint16 __ovld __purefn vload16(size_t offset, const __global uint *p);
+long16 __ovld __purefn vload16(size_t offset, const __global long *p);
+ulong16 __ovld __purefn vload16(size_t offset, const __global ulong *p);
+float16 __ovld __purefn vload16(size_t offset, const __global float *p);
+char2 __ovld __purefn vload2(size_t offset, const __local char *p);
+uchar2 __ovld __purefn vload2(size_t offset, const __local uchar *p);
+short2 __ovld __purefn vload2(size_t offset, const __local short *p);
+ushort2 __ovld __purefn vload2(size_t offset, const __local ushort *p);
+int2 __ovld __purefn vload2(size_t offset, const __local int *p);
+uint2 __ovld __purefn vload2(size_t offset, const __local uint *p);
+long2 __ovld __purefn vload2(size_t offset, const __local long *p);
+ulong2 __ovld __purefn vload2(size_t offset, const __local ulong *p);
+float2 __ovld __purefn vload2(size_t offset, const __local float *p);
+char3 __ovld __purefn vload3(size_t offset, const __local char *p);
+uchar3 __ovld __purefn vload3(size_t offset, const __local uchar *p);
+short3 __ovld __purefn vload3(size_t offset, const __local short *p);
+ushort3 __ovld __purefn vload3(size_t offset, const __local ushort *p);
+int3 __ovld __purefn vload3(size_t offset, const __local int *p);
+uint3 __ovld __purefn vload3(size_t offset, const __local uint *p);
+long3 __ovld __purefn vload3(size_t offset, const __local long *p);
+ulong3 __ovld __purefn vload3(size_t offset, const __local ulong *p);
+float3 __ovld __purefn vload3(size_t offset, const __local float *p);
+char4 __ovld __purefn vload4(size_t offset, const __local char *p);
+uchar4 __ovld __purefn vload4(size_t offset, const __local uchar *p);
+short4 __ovld __purefn vload4(size_t offset, const __local short *p);
+ushort4 __ovld __purefn vload4(size_t offset, const __local ushort *p);
+int4 __ovld __purefn vload4(size_t offset, const __local int *p);
+uint4 __ovld __purefn vload4(size_t offset, const __local uint *p);
+long4 __ovld __purefn vload4(size_t offset, const __local long *p);
+ulong4 __ovld __purefn vload4(size_t offset, const __local ulong *p);
+float4 __ovld __purefn vload4(size_t offset, const __local float *p);
+char8 __ovld __purefn vload8(size_t offset, const __local char *p);
+uchar8 __ovld __purefn vload8(size_t offset, const __local uchar *p);
+short8 __ovld __purefn vload8(size_t offset, const __local short *p);
+ushort8 __ovld __purefn vload8(size_t offset, const __local ushort *p);
+int8 __ovld __purefn vload8(size_t offset, const __local int *p);
+uint8 __ovld __purefn vload8(size_t offset, const __local uint *p);
+long8 __ovld __purefn vload8(size_t offset, const __local long *p);
+ulong8 __ovld __purefn vload8(size_t offset, const __local ulong *p);
+float8 __ovld __purefn vload8(size_t offset, const __local float *p);
+char16 __ovld __purefn vload16(size_t offset, const __local char *p);
+uchar16 __ovld __purefn vload16(size_t offset, const __local uchar *p);
+short16 __ovld __purefn vload16(size_t offset, const __local short *p);
+ushort16 __ovld __purefn vload16(size_t offset, const __local ushort *p);
+int16 __ovld __purefn vload16(size_t offset, const __local int *p);
+uint16 __ovld __purefn vload16(size_t offset, const __local uint *p);
+long16 __ovld __purefn vload16(size_t offset, const __local long *p);
+ulong16 __ovld __purefn vload16(size_t offset, const __local ulong *p);
+float16 __ovld __purefn vload16(size_t offset, const __local float *p);
+char2 __ovld __purefn vload2(size_t offset, const __private char *p);
+uchar2 __ovld __purefn vload2(size_t offset, const __private uchar *p);
+short2 __ovld __purefn vload2(size_t offset, const __private short *p);
+ushort2 __ovld __purefn vload2(size_t offset, const __private ushort *p);
+int2 __ovld __purefn vload2(size_t offset, const __private int *p);
+uint2 __ovld __purefn vload2(size_t offset, const __private uint *p);
+long2 __ovld __purefn vload2(size_t offset, const __private long *p);
+ulong2 __ovld __purefn vload2(size_t offset, const __private ulong *p);
+float2 __ovld __purefn vload2(size_t offset, const __private float *p);
+char3 __ovld __purefn vload3(size_t offset, const __private char *p);
+uchar3 __ovld __purefn vload3(size_t offset, const __private uchar *p);
+short3 __ovld __purefn vload3(size_t offset, const __private short *p);
+ushort3 __ovld __purefn vload3(size_t offset, const __private ushort *p);
+int3 __ovld __purefn vload3(size_t offset, const __private int *p);
+uint3 __ovld __purefn vload3(size_t offset, const __private uint *p);
+long3 __ovld __purefn vload3(size_t offset, const __private long *p);
+ulong3 __ovld __purefn vload3(size_t offset, const __private ulong *p);
+float3 __ovld __purefn vload3(size_t offset, const __private float *p);
+char4 __ovld __purefn vload4(size_t offset, const __private char *p);
+uchar4 __ovld __purefn vload4(size_t offset, const __private uchar *p);
+short4 __ovld __purefn vload4(size_t offset, const __private short *p);
+ushort4 __ovld __purefn vload4(size_t offset, const __private ushort *p);
+int4 __ovld __purefn vload4(size_t offset, const __private int *p);
+uint4 __ovld __purefn vload4(size_t offset, const __private uint *p);
+long4 __ovld __purefn vload4(size_t offset, const __private long *p);
+ulong4 __ovld __purefn vload4(size_t offset, const __private ulong *p);
+float4 __ovld __purefn vload4(size_t offset, const __private float *p);
+char8 __ovld __purefn vload8(size_t offset, const __private char *p);
+uchar8 __ovld __purefn vload8(size_t offset, const __private uchar *p);
+short8 __ovld __purefn vload8(size_t offset, const __private short *p);
+ushort8 __ovld __purefn vload8(size_t offset, const __private ushort *p);
+int8 __ovld __purefn vload8(size_t offset, const __private int *p);
+uint8 __ovld __purefn vload8(size_t offset, const __private uint *p);
+long8 __ovld __purefn vload8(size_t offset, const __private long *p);
+ulong8 __ovld __purefn vload8(size_t offset, const __private ulong *p);
+float8 __ovld __purefn vload8(size_t offset, const __private float *p);
+char16 __ovld __purefn vload16(size_t offset, const __private char *p);
+uchar16 __ovld __purefn vload16(size_t offset, const __private uchar *p);
+short16 __ovld __purefn vload16(size_t offset, const __private short *p);
+ushort16 __ovld __purefn vload16(size_t offset, const __private ushort *p);
+int16 __ovld __purefn vload16(size_t offset, const __private int *p);
+uint16 __ovld __purefn vload16(size_t offset, const __private uint *p);
+long16 __ovld __purefn vload16(size_t offset, const __private long *p);
+ulong16 __ovld __purefn vload16(size_t offset, const __private ulong *p);
+float16 __ovld __purefn vload16(size_t offset, const __private float *p);
+
+#ifdef cl_khr_fp64
+double2 __ovld __purefn vload2(size_t offset, const __global double *p);
+double3 __ovld __purefn vload3(size_t offset, const __global double *p);
+double4 __ovld __purefn vload4(size_t offset, const __global double *p);
+double8 __ovld __purefn vload8(size_t offset, const __global double *p);
+double16 __ovld __purefn vload16(size_t offset, const __global double *p);
+double2 __ovld __purefn vload2(size_t offset, const __local double *p);
+double3 __ovld __purefn vload3(size_t offset, const __local double *p);
+double4 __ovld __purefn vload4(size_t offset, const __local double *p);
+double8 __ovld __purefn vload8(size_t offset, const __local double *p);
+double16 __ovld __purefn vload16(size_t offset, const __local double *p);
+double2 __ovld __purefn vload2(size_t offset, const __private double *p);
+double3 __ovld __purefn vload3(size_t offset, const __private double *p);
+double4 __ovld __purefn vload4(size_t offset, const __private double *p);
+double8 __ovld __purefn vload8(size_t offset, const __private double *p);
+double16 __ovld __purefn vload16(size_t offset, const __private double *p);
+#endif //cl_khr_fp64
+
+#ifdef cl_khr_fp16
+half __ovld __purefn vload(size_t offset, const __global half *p);
+half2 __ovld __purefn vload2(size_t offset, const __global half *p);
+half3 __ovld __purefn vload3(size_t offset, const __global half *p);
+half4 __ovld __purefn vload4(size_t offset, const __global half *p);
+half8 __ovld __purefn vload8(size_t offset, const __global half *p);
+half16 __ovld __purefn vload16(size_t offset, const __global half *p);
+half __ovld __purefn vload(size_t offset, const __local half *p);
+half2 __ovld __purefn vload2(size_t offset, const __local half *p);
+half3 __ovld __purefn vload3(size_t offset, const __local half *p);
+half4 __ovld __purefn vload4(size_t offset, const __local half *p);
+half8 __ovld __purefn vload8(size_t offset, const __local half *p);
+half16 __ovld __purefn vload16(size_t offset, const __local half *p);
+half __ovld __purefn vload(size_t offset, const __private half *p);
+half2 __ovld __purefn vload2(size_t offset, const __private half *p);
+half3 __ovld __purefn vload3(size_t offset, const __private half *p);
+half4 __ovld __purefn vload4(size_t offset, const __private half *p);
+half8 __ovld __purefn vload8(size_t offset, const __private half *p);
+half16 __ovld __purefn vload16(size_t offset, const __private half *p);
 #endif //cl_khr_fp16
 #endif //defined(__opencl_c_generic_address_space)
 
 #if defined(__opencl_c_generic_address_space)
 void __ovld vstore2(char2 data, size_t offset, char *p);
 void __ovld vstore2(uchar2 data, size_t offset, uchar *p);
 void __ovld vstore2(short2 data, size_t offset, short *p);
 void __ovld vstore2(ushort2 data, size_t offset, ushort *p);

 /**
  * Read sizeof (half) bytes of data from address
  * (p + offset). The data read is interpreted as a
  * half value. The half value is converted to a
  * float value and the float value is returned.
  * The read address computed as (p + offset)
  * must be 16-bit aligned.
  */
-float __ovld vload_half(size_t offset, const __constant half *p);
+float __ovld __purefn vload_half(size_t offset, const __constant half *p);
 #if defined(__opencl_c_generic_address_space)
-float __ovld vload_half(size_t offset, const half *p);
+float __ovld __purefn vload_half(size_t offset, const half *p);
 #else
-float __ovld vload_half(size_t offset, const __global half *p);
-float __ovld vload_half(size_t offset, const __local half *p);
-float __ovld vload_half(size_t offset, const __private half *p);
+float __ovld __purefn vload_half(size_t offset, const __global half *p);
+float __ovld __purefn vload_half(size_t offset, const __local half *p);
+float __ovld __purefn vload_half(size_t offset, const __private half *p);
 #endif //defined(__opencl_c_generic_address_space)
 
 /**
  * Read sizeof (halfn) bytes of data from address
  * (p + (offset * n)). The data read is interpreted
  * as a halfn value. The halfn value read is
  * converted to a floatn value and the floatn
  * value is returned. The read address computed
  * as (p + (offset * n)) must be 16-bit aligned.
  */
-float2 __ovld vload_half2(size_t offset, const __constant half *p);
-float3 __ovld vload_half3(size_t offset, const __constant half *p);
-float4 __ovld vload_half4(size_t offset, const __constant half *p);
-float8 __ovld vload_half8(size_t offset, const __constant half *p);
-float16 __ovld vload_half16(size_t offset, const __constant half *p);
+float2 __ovld __purefn vload_half2(size_t offset, const __constant half *p);
+float3 __ovld __purefn vload_half3(size_t offset, const __constant half *p);
+float4 __ovld __purefn vload_half4(size_t offset, const __constant half *p);
+float8 __ovld __purefn vload_half8(size_t offset, const __constant half *p);
+float16 __ovld __purefn vload_half16(size_t offset, const __constant half *p);
 #if defined(__opencl_c_generic_address_space)
-float2 __ovld vload_half2(size_t offset, const half *p);
-float3 __ovld vload_half3(size_t offset, const half *p);
-float4 __ovld vload_half4(size_t offset, const half *p);
-float8 __ovld vload_half8(size_t offset, const half *p);
-float16 __ovld vload_half16(size_t offset, const half *p);
+float2 __ovld __purefn vload_half2(size_t offset, const half *p);
+float3 __ovld __purefn vload_half3(size_t offset, const half *p);
+float4 __ovld __purefn vload_half4(size_t offset, const half *p);
+float8 __ovld __purefn vload_half8(size_t offset, const half *p);
+float16 __ovld __purefn vload_half16(size_t offset, const half *p);
 #else
-float2 __ovld vload_half2(size_t offset, const __global half *p);
-float3 __ovld vload_half3(size_t offset, const __global half *p);
-float4 __ovld vload_half4(size_t offset, const __global half *p);
-float8 __ovld vload_half8(size_t offset, const __global half *p);
-float16 __ovld vload_half16(size_t offset, const __global half *p);
-float2 __ovld vload_half2(size_t offset, const __local half *p);
-float3 __ovld vload_half3(size_t offset, const __local half *p);
-float4 __ovld vload_half4(size_t offset, const __local half *p);
-float8 __ovld vload_half8(size_t offset, const __local half *p);
-float16 __ovld vload_half16(size_t offset, const __local half *p);
-float2 __ovld vload_half2(size_t offset, const __private half *p);
-float3 __ovld vload_half3(size_t offset, const __private half *p);
-float4 __ovld vload_half4(size_t offset, const __private half *p);
-float8 __ovld vload_half8(size_t offset, const __private half *p);
-float16 __ovld vload_half16(size_t offset, const __private half *p);
+float2 __ovld __purefn vload_half2(size_t offset, const __global half *p);
+float3 __ovld __purefn vload_half3(size_t offset, const __global half *p);
+float4 __ovld __purefn vload_half4(size_t offset, const __global half *p);
+float8 __ovld __purefn vload_half8(size_t offset, const __global half *p);
+float16 __ovld __purefn vload_half16(size_t offset, const __global half *p);
+float2 __ovld __purefn vload_half2(size_t offset, const __local half *p);
+float3 __ovld __purefn vload_half3(size_t offset, const __local half *p);
+float4 __ovld __purefn vload_half4(size_t offset, const __local half *p);
+float8 __ovld __purefn vload_half8(size_t offset, const __local half *p);
+float16 __ovld __purefn vload_half16(size_t offset, const __local half *p);
+float2 __ovld __purefn vload_half2(size_t offset, const __private half *p);
+float3 __ovld __purefn vload_half3(size_t offset, const __private half *p);
+float4 __ovld __purefn vload_half4(size_t offset, const __private half *p);
+float8 __ovld __purefn vload_half8(size_t offset, const __private half *p);
+float16 __ovld __purefn vload_half16(size_t offset, const __private half *p);
 #endif //defined(__opencl_c_generic_address_space)
 
 /**
  * The float value given by data is first
  * converted to a half value using the appropriate
  * rounding mode. The half value is then written
  * to address computed as (p + offset). The
  * address computed as (p + offset) must be 16-

  * value and the floatn value is returned.
  * The address computed as (p + (offset * n))
  * must be aligned to sizeof (halfn) bytes.
  * For n = 3, vloada_half3 reads a half3 from
  * address (p + (offset * 4)) and returns a float3.
  * The address computed as (p + (offset * 4))
  * must be aligned to sizeof (half) * 4 bytes.
  */
-float2 __ovld vloada_half2(size_t offset, const __constant half *p);
-float3 __ovld vloada_half3(size_t offset, const __constant half *p);
-float4 __ovld vloada_half4(size_t offset, const __constant half *p);
-float8 __ovld vloada_half8(size_t offset, const __constant half *p);
-float16 __ovld vloada_half16(size_t offset, const __constant half *p);
+float2 __ovld __purefn vloada_half2(size_t offset, const __constant half *p);
+float3 __ovld __purefn vloada_half3(size_t offset, const __constant half *p);
+float4 __ovld __purefn vloada_half4(size_t offset, const __constant half *p);
+float8 __ovld __purefn vloada_half8(size_t offset, const __constant half *p);
+float16 __ovld __purefn vloada_half16(size_t offset, const __constant half *p);
 #if defined(__opencl_c_generic_address_space)
-float2 __ovld vloada_half2(size_t offset, const half *p);
-float3 __ovld vloada_half3(size_t offset, const half *p);
-float4 __ovld vloada_half4(size_t offset, const half *p);
-float8 __ovld vloada_half8(size_t offset, const half *p);
-float16 __ovld vloada_half16(size_t offset, const half *p);
+float2 __ovld __purefn vloada_half2(size_t offset, const half *p);
+float3 __ovld __purefn vloada_half3(size_t offset, const half *p);
+float4 __ovld __purefn vloada_half4(size_t offset, const half *p);
+float8 __ovld __purefn vloada_half8(size_t offset, const half *p);
+float16 __ovld __purefn vloada_half16(size_t offset, const half *p);
 #else
-float2 __ovld vloada_half2(size_t offset, const __global half *p);
-float3 __ovld vloada_half3(size_t offset, const __global half *p);
-float4 __ovld vloada_half4(size_t offset, const __global half *p);
-float8 __ovld vloada_half8(size_t offset, const __global half *p);
-float16 __ovld vloada_half16(size_t offset, const __global half *p);
-float2 __ovld vloada_half2(size_t offset, const __local half *p);
-float3 __ovld vloada_half3(size_t offset, const __local half *p);
-float4 __ovld vloada_half4(size_t offset, const __local half *p);
-float8 __ovld vloada_half8(size_t offset, const __local half *p);
-float16 __ovld vloada_half16(size_t offset, const __local half *p);
-float2 __ovld vloada_half2(size_t offset, const __private half *p);
-float3 __ovld vloada_half3(size_t offset, const __private half *p);
-float4 __ovld vloada_half4(size_t offset, const __private half *p);
-float8 __ovld vloada_half8(size_t offset, const __private half *p);
-float16 __ovld vloada_half16(size_t offset, const __private half *p);
+float2 __ovld __purefn vloada_half2(size_t offset, const __global half *p);
+float3 __ovld __purefn vloada_half3(size_t offset, const __global half *p);
+float4 __ovld __purefn vloada_half4(size_t offset, const __global half *p);
+float8 __ovld __purefn vloada_half8(size_t offset, const __global half *p);
+float16 __ovld __purefn vloada_half16(size_t offset, const __global half *p);
+float2 __ovld __purefn vloada_half2(size_t offset, const __local half *p);
+float3 __ovld __purefn vloada_half3(size_t offset, const __local half *p);
+float4 __ovld __purefn vloada_half4(size_t offset, const __local half *p);
+float8 __ovld __purefn vloada_half8(size_t offset, const __local half *p);
+float16 __ovld __purefn vloada_half16(size_t offset, const __local half *p);
+float2 __ovld __purefn vloada_half2(size_t offset, const __private half *p);
+float3 __ovld __purefn vloada_half3(size_t offset, const __private half *p);
+float4 __ovld __purefn vloada_half4(size_t offset, const __private half *p);
+float8 __ovld __purefn vloada_half8(size_t offset, const __private half *p);
+float16 __ovld __purefn vloada_half16(size_t offset, const __private half *p);
 #endif //defined(__opencl_c_generic_address_space)
 
 /**
  * The floatn value given by data is converted to
  * a halfn value using the appropriate rounding
  * mode.
  * For n = 1, 2, 4, 8 and 16, the halfn value is
  * written to the address computed as (p + (offset

clang/lib/Sema/OpenCLBuiltins.td

 //--------------------------------------------------------------------
 // OpenCL v1.1 s6.11.7, v1.2 s6.12.7, v2.0 s6.13.7 - Vector Data Load and Store Functions
 // OpenCL Extension v1.1 s9.3.6 and s9.6.6, v1.2 s9.5.6, v2.0 s5.1.6 and s6.1.6 - Vector Data Load and Store Functions
 // --- Table 15 ---
 multiclass VloadVstore<list<AddressSpace> addrspaces, bit defStores> {
   foreach AS = addrspaces in {
     foreach VSize = [2, 3, 4, 8, 16] in {
       foreach name = ["vload" # VSize] in {
-        def : Builtin<name, [VectorType<Char, VSize>, Size, PointerType<ConstType<Char>, AS>]>;
-        def : Builtin<name, [VectorType<UChar, VSize>, Size, PointerType<ConstType<UChar>, AS>]>;
-        def : Builtin<name, [VectorType<Short, VSize>, Size, PointerType<ConstType<Short>, AS>]>;
-        def : Builtin<name, [VectorType<UShort, VSize>, Size, PointerType<ConstType<UShort>, AS>]>;
-        def : Builtin<name, [VectorType<Int, VSize>, Size, PointerType<ConstType<Int>, AS>]>;
-        def : Builtin<name, [VectorType<UInt, VSize>, Size, PointerType<ConstType<UInt>, AS>]>;
-        def : Builtin<name, [VectorType<Long, VSize>, Size, PointerType<ConstType<Long>, AS>]>;
-        def : Builtin<name, [VectorType<ULong, VSize>, Size, PointerType<ConstType<ULong>, AS>]>;
-        def : Builtin<name, [VectorType<Float, VSize>, Size, PointerType<ConstType<Float>, AS>]>;
-        def : Builtin<name, [VectorType<Double, VSize>, Size, PointerType<ConstType<Double>, AS>]>;
-        def : Builtin<name, [VectorType<Half, VSize>, Size, PointerType<ConstType<Half>, AS>]>;
+        def : Builtin<name, [VectorType<Char, VSize>, Size, PointerType<ConstType<Char>, AS>], Attr.Pure>;
+        def : Builtin<name, [VectorType<UChar, VSize>, Size, PointerType<ConstType<UChar>, AS>], Attr.Pure>;
+        def : Builtin<name, [VectorType<Short, VSize>, Size, PointerType<ConstType<Short>, AS>], Attr.Pure>;
+        def : Builtin<name, [VectorType<UShort, VSize>, Size, PointerType<ConstType<UShort>, AS>], Attr.Pure>;
+        def : Builtin<name, [VectorType<Int, VSize>, Size, PointerType<ConstType<Int>, AS>], Attr.Pure>;
+        def : Builtin<name, [VectorType<UInt, VSize>, Size, PointerType<ConstType<UInt>, AS>], Attr.Pure>;
+        def : Builtin<name, [VectorType<Long, VSize>, Size, PointerType<ConstType<Long>, AS>], Attr.Pure>;
+        def : Builtin<name, [VectorType<ULong, VSize>, Size, PointerType<ConstType<ULong>, AS>], Attr.Pure>;
+        def : Builtin<name, [VectorType<Float, VSize>, Size, PointerType<ConstType<Float>, AS>], Attr.Pure>;
+        def : Builtin<name, [VectorType<Double, VSize>, Size, PointerType<ConstType<Double>, AS>], Attr.Pure>;
+        def : Builtin<name, [VectorType<Half, VSize>, Size, PointerType<ConstType<Half>, AS>], Attr.Pure>;
       }
       if defStores then {
         foreach name = ["vstore" # VSize] in {
           def : Builtin<name, [Void, VectorType<Char, VSize>, Size, PointerType<Char, AS>]>;
           def : Builtin<name, [Void, VectorType<UChar, VSize>, Size, PointerType<UChar, AS>]>;
           def : Builtin<name, [Void, VectorType<Short, VSize>, Size, PointerType<Short, AS>]>;
           def : Builtin<name, [Void, VectorType<UShort, VSize>, Size, PointerType<UShort, AS>]>;
           def : Builtin<name, [Void, VectorType<Int, VSize>, Size, PointerType<Int, AS>]>;

 let MinVersion = CL20 in {
   defm : VloadVstore<[GenericAS], 1>;
 }
 // vload with constant address space is available regardless of version.
 defm : VloadVstore<[ConstantAS], 0>;
 
 multiclass VloadVstoreHalf<list<AddressSpace> addrspaces, bit defStores> {
   foreach AS = addrspaces in {
-    def : Builtin<"vload_half", [Float, Size, PointerType<ConstType<Half>, AS>]>;
+    def : Builtin<"vload_half", [Float, Size, PointerType<ConstType<Half>, AS>], Attr.Pure>;
     foreach VSize = [2, 3, 4, 8, 16] in {
       foreach name = ["vload_half" # VSize, "vloada_half" # VSize] in {
-        def : Builtin<name, [VectorType<Float, VSize>, Size, PointerType<ConstType<Half>, AS>]>;
+        def : Builtin<name, [VectorType<Float, VSize>, Size, PointerType<ConstType<Half>, AS>], Attr.Pure>;
       }
     }
     if defStores then {
       foreach rnd = ["", "_rte", "_rtz", "_rtp", "_rtn"] in {
         foreach name = ["vstore_half" # rnd] in {
           def : Builtin<name, [Void, Float, Size, PointerType<Half, AS>]>;
           def : Builtin<name, [Void, Double, Size, PointerType<Half, AS>]>;
         }

 }
 
 let MaxVersion = CL20 in {
   defm : VloadVstoreHalf<[GlobalAS, LocalAS, PrivateAS], 1>;
 }
 let MinVersion = CL20 in {
   defm : VloadVstoreHalf<[GenericAS], 1>;
 }
-// vload with constant address space is available regardless of version.
+// vload_half and vloada_half with constant address space are available regardless of version.
 defm : VloadVstoreHalf<[ConstantAS], 0>;
 
 // OpenCL v3.0 s6.15.8 - Synchronization Functions.
 def : Builtin<"barrier", [Void, MemFenceFlags], Attr.Convergent>;
 let MinVersion = CL20 in {
   def : Builtin<"work_group_barrier", [Void, MemFenceFlags], Attr.Convergent>;
   def : Builtin<"work_group_barrier", [Void, MemFenceFlags, MemoryScope], Attr.Convergent>;
 }