thrust: add 4-iterator mismatch overloads (bounded last2)#8504
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edenfunf wants to merge 2 commits intoNVIDIA:mainfrom
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thrust: add 4-iterator mismatch overloads (bounded last2)#8504edenfunf wants to merge 2 commits intoNVIDIA:mainfrom
edenfunf wants to merge 2 commits intoNVIDIA:mainfrom
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Add `thrust::mismatch(first1, last1, first2, last2)` and `thrust::mismatch(first1, last1, first2, last2, pred)` overloads (with and without execution policy) to match the C++14 standard 4-iterator form that prevents reading past a shorter second range. CUDA-backend: uses `min(n1, n2)` to bound a zip_iterator fed to `find_if_not`, keeping the same single-pass GPU kernel as the existing 3-iterator path. Generic fallback: computes distances, advances a bounded last1 to `min(n1,n2)`, then delegates to the existing 3-iterator `find_if_not` path — forward-iterator safe. Public API declarations and Doxygen docs added to `mismatch.h`; dispatch wired in `mismatch.inl`. Tests: `TestMismatchBoundedSimple` (DECLARE_VECTOR_UNITTEST) covers equal-length, shorter range1, shorter range2, early mismatch, with predicate, and empty range cases. `TestMismatchBoundedWithExec` exercises the device execution-policy path and predicate overload. Closes NVIDIA#3601
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@davebayer Hi, could you please take a look at this PR when you have time?Thanks! |
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Summary
Adds the C++14 4-iterator form of
thrust::mismatchthat accepts an explicit end iterator for the second range, preventing out-of-bounds reads when the two ranges have different lengths.Closes #3601
New overloads
Implementation
cuda/detail/mismatch.h)min(n1,n2)bounds azip_iteratorfed tofind_if_not??single-pass GPU kernel, same pattern as existing 3-iterator pathgeneric/mismatch.inl)advancea boundedlast1tomin(n1,n2), delegate to existing 3-iterator path ??forward-iterator safemismatch.h/mismatch.inl)Tests (all pass on RTX 5070 / sm_89)
TestMismatchBoundedSimple(DECLARE_VECTOR_UNITTEST??host + device + custom_numeric):TestMismatchBoundedWithExec(DECLARE_UNITTEST??device execution policy):thrust::devicethrust::device+ predicate