chore(gpu): fix static analysis warnings

[pdroalves]

Summary

Fix minor warnings raised by static analysis across the CUDA backends.

Value-initialized structs:

• cudaPointerAttributes attr{} in device.cu (5 instances) to avoid reading uninitialized fields
• cudaDeviceProp prop{} in bootstrapping_key.cu to avoid reading uninitialized fields
• cudaDeviceProp deviceProp{} in helper_multi_gpu.cu to avoid reading uninitialized fields
• cudaDeviceProp device_prop{} in device.cu (tfhe-cuda-common) to avoid reading uninitialized fields

Deprecated C headers replaced with C++ equivalents:

• <stdint.h> → <cstdint> in helper_profile.cu
• <stdio.h> → <cstdio> in programmable_bootstrap_classic.cu

Deprecated CUDA types replaced:

• ulonglong4 → ulonglong4_16a in linearalgebra/multiplication.cu (2 instances) and polynomial/dot_product.cuh (1 instance)

Narrowing conversion fixes:

• blockIdx.y → static_cast<int>(blockIdx.y) in programmable_bootstrap.cu
• threadIdx.x + blockIdx.x * blockDim.x → static_cast<int>(...) in device.cu
• 0xff000000 | (r << 16) | ... → static_cast<int>(...) in helper_profile.cu

auto with cast expressions:

• double2 *buffer = (double2 *)cuda_malloc_async(...) → auto *buffer = ... in bootstrapping_key.cu
• __uint128_t *d_standard = (__uint128_t *)cuda_malloc_async(...) → auto *d_standard = ... in bootstrapping_key.cu

Erroneous const on cudaStream_t parameter:

• cudaStream_t const stream → cudaStream_t stream in radix_ciphertext.h and radix_ciphertext.cu (cudaStream_t is a pointer typedef, so top-level const is misleading)

Unused includes removed:

• #include <omp.h> from helper_multi_gpu.cu
• #include <iostream> from integer/scalar_comparison.cu
• #include "ciphertext.h" from pbs/programmable_bootstrap_classic.cu

Unused parameter names commented out:

• group and support_dsm in 3 grid_group template specializations in programmable_bootstrap.cu
• polynomial_size in integer/scalar_mul.cu
• num_radix in integer/multiplication.cu (declaration updated in integer_utilities.h)
• num_inputs in kreyvium/kreyvium.cu and trivium/trivium.cu (2 functions each)

Missing Doxygen @param entries:

• oprf.cu: added @param for streams, message_modulus, carry_modulus, allocate_gpu_memory, bsks, ksks
• shuffle.cu: added @param for streams, bsks, ksks, lwe_flattened_encryptions_of_zero_compact_array_in, rerand_ksks
• integer.cu: added @param for stream, gpu_index

Parameter name mismatches between declarations and definitions:

• stream_v/_input1/_input2/_output → stream/input1/input2/output in 4 fourier polynomial functions in bootstrapping_key.cu (local casts use short names s, in1, in2, out, buf)
• mem_ptr → buffer in PBS scratch/cleanup/execute functions across programmable_bootstrap_classic.cu, programmable_bootstrap_classic_128.cu, programmable_bootstrap_multibit.cu, programmable_bootstrap_multibit_128.cu (local casts use pbs_buf to avoid shadowing the pbs_buffer type)
• pbs_buffer → buffer in multibit noise-test wrapper functions in programmable_bootstrap_multibit.h and .cu
• uses_trivial_indices → uses_trivial_indexes in 2 keyswitch functions in keyswitch.cu
• num_radix_blocks → lwe_ciphertext_count in 2 comparison functions in comparison.cu
• num_radix_blocks → input_lwe_ciphertext_count, num_many_lut → num_luts, original_num_blocks → num_original_blocks in 3 integer functions in integer.cu
• mem → mem_ptr in scalar_mul.cu
• glwe_lhs → poly_lhs in multiplication.cu
• Updated bindings.rs (auto-generated) to reflect header changes

Validation

• make pcc_gpu passes (doxygen check, formatting)
• cargo check -p tfhe-cuda-backend passes

[github-actions]

✅ Backward-compat snapshot: everything looks good! No backward-compatibility issues detected.

[github-actions]

✅ Forward compatibility matrix unchanged: it still matches the committed baseline.

Matrix

Which released versions can load data produced by this branch. A ❌ is not a failure by itself: it only means forward compatibility is not (or no longer) provided for that type. What matters is whether it was reviewed.

TYPE	1.5.5	1.6.3	1.7.0
CompactPublicKey	❌	✅	✅
CompactPkeCrs	✅	✅	✅
ProvenCompactCiphertextList	❌	✅	✅

[github-actions]

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