DPCT1089
Contents
DPCT1089#
Message#
The value of the sub-group size attribute argument <argument name> cannot be evaluated. Replace dpct_placeholder
with an integral constant expression.
Detailed Help#
The argument to the attribute must be an integral constant expression. This warning is emitted when Intel® DPC++ Compatibility Tool cannot evaluate the value of the sub-group size argument as an integral constant expression. Check if the sub-group size attribute argument can be replaced by an integral constant expression, and if not, redesign the code logic.
For example, this original CUDA* code:
1 _global_ void kernel(int WarpSize) { int Input, Output, Lane; ... Output = __shfl(Input, Lane, WarpSize); }
2 ...
3 if(condition)
4 { kernel<<<GirdSize, BlockSize>>>(16); }
5 else
6 { kernel<<<GirdSize, BlockSize>>>(32); }
results in the following migrated SYCL* code:
1 void kernel(int WarpSize, sycl::nd_item<3> item_ct1)
2 { int Input, Output, Lane; ... Output = Item_ct1.get_sub_group().shuffle(Input, Lane); }
3 ...
4 if(condition) {
5 /* DPCT1089 */
6 q_ct1.parallel_for(
7 sycl::nd_range<3>(GridSize * BlockSize, BlockSize),
8 [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(dpct_placeholder)]] { kernel(16, item_ct1); });
9 } else {
10 /* DPCT1089 */
11 q_ct1.parallel_for(
12 sycl::nd_range<3>(GridSize * BlockSize, BlockSize),
13 [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(dpct_placeholder)]] { kernel(32, item_ct1); }
which is manually adjusted to:
1 void kernel(int WarpSize, sycl::nd_item<3> item_ct1) { int Input, Output, Lane; ... Output = Item_ct1.get_sub_group().shuffle(Input, Lane); }
2 ...
3 if(condition) {
4 /* DPCT1089 */
5 q_ct1.parallel_for(
6 sycl::nd_range<3>(GridSize * BlockSize, BlockSize),
7 [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(16)]]
8 { kernel(16, item_ct1); }
9 );
10 } else {
11 /* DPCT1089 */
12 q_ct1.parallel_for(
13 sycl::nd_range<3>(GridSize * BlockSize, BlockSize),
14 [=](sycl::nd_item<3> item_ct1) [[intel::reqd_sub_group_size(32)]]
15 { kernel(32, item_ct1); }
Suggestions to Fix#
Code requires manual fix. Replace “dpct_placeholder” with an integral constant expression.