[BUG]: UB in thrust tests caused by out-of range conversion from FP types to integers.

[Artem-B]

Is this a duplicate?

• I confirmed there appear to be no duplicate issues for this bug and that I agree to the Code of Conduct

Type of Bug

Something else

Component

Thrust

Describe the bug

random_integers<fp-type>() may generate values not representable as an integer type, which results in undefined behavior when we attempt to cast them to integer type later on.

E.g.:

cccl/thrust/testing/for_each.cu

Lines 170 to 174 in 59deb06

	thrust::host_vector<T> h_input = unittest::random_integers<T>(n);
	for (size_t i = 0; i < n; i++)
	{
	h_input[i] = ((size_t) h_input[i]) % output_size;

UBsan reported an error on (size_t)h_input[i]:

third_party/gpus/cccl/v2_6_0/thrust/testing/for_each.cu.cc:205:28: runtime error: 2.35321e+38 is outside the range of representable values of type 'unsigned long'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior third_party/gpus/cccl/v2_6_0/thrust/testing/for_each.cu.cc:205:28

How to Reproduce

Stock thrust tests with clang, UBsan, and disabled optimizations.

Expected behavior

Avoiding undefined behavior is a good idea in general.

Reproduction link

No response

Operating System

No response

nvidia-smi output

No response

NVCC version

No response