onnxruntime

233d95d0 - [CUDA] Fix fpA_intB internal test build: typed nullptr for TryMatMulNBits bias (#29596)

[CUDA] Fix fpA_intB internal test build: typed nullptr for TryMatMulNBits bias (#29596) ### Description Fixes a build break in the internal CUDA-EP unit-test module (`onnxruntime_ENABLE_CUDA_EP_INTERNAL_TESTS=ON`). `TryMatMulNBits` in `matmul_nbits.cuh` is a function template: ```cpp template <class T> bool TryMatMulNBits(int bits, T* output, const T* a_data, const uint8_t* b_data_quant, const T* scales_data, const uint8_t* zero_points, const T* bias_data, int m, int n, int k, int block_size, size_t shared_mem_per_block, cudaStream_t stream); ``` The MoE router bias fusion change (#29170) added the `const T* bias_data` parameter. The internal CUDA-EP test `fpA_intB_gemm_kernel_test.cc` calls this with a bare `nullptr` for `bias_data`. Since `nullptr` has type `std::nullptr_t` (not a pointer), it fails to match `const T*` during template argument deduction, even though `T` is deducible from the other arguments. GCC reports: ``` error: no matching function for call to 'TryMatMulNBits(...)' note: mismatched types 'const T*' and 'std::nullptr_t' ``` This is compiled only when `onnxruntime_ENABLE_CUDA_EP_INTERNAL_TESTS=ON`, so the internal CUDA-EP unit-test build leg is currently broken on main. ### Key Changes - Cast the `bias_data` argument at the call site to `static_cast<const AType*>(nullptr)` so `T` deduces correctly and the existing no-bias path is exercised unchanged. ### Motivation and Context Restores the ability to build and run the internal CUDA-EP unit tests (e.g. `./onnxruntime_provider_test --gtest_filter=CUDA_EP_Unittest.*`). ### Validation - Reproduced the exact "no matching function / mismatched types 'const T*' and 'std::nullptr_t'" deduction failure with a minimal template repro; confirmed the typed-nullptr cast compiles cleanly.