[ADT] Consolidate uninitialized_copy in SmallVector (NFC)#161043
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kazutakahirata merged 1 commit intoOct 1, 2025
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This patch consolidates two implementations of uninitialized_copy into a single template function.
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@llvm/pr-subscribers-llvm-adt Author: Kazu Hirata (kazutakahirata) ChangesThis patch consolidates two implementations of uninitialized_copy into Full diff: https://github.com/llvm/llvm-project/pull/161043.diff 1 Files Affected:
diff --git a/llvm/include/llvm/ADT/SmallVector.h b/llvm/include/llvm/ADT/SmallVector.h
index 36b324355ee10..8ccbaf8652193 100644
--- a/llvm/include/llvm/ADT/SmallVector.h
+++ b/llvm/include/llvm/ADT/SmallVector.h
@@ -501,25 +501,22 @@ class SmallVectorTemplateBase<T, true> : public SmallVectorTemplateCommon<T> {
/// Copy the range [I, E) onto the uninitialized memory
/// starting with "Dest", constructing elements into it as needed.
- template<typename It1, typename It2>
+ template <typename It1, typename It2>
static void uninitialized_copy(It1 I, It1 E, It2 Dest) {
- // Arbitrary iterator types; just use the basic implementation.
- std::uninitialized_copy(I, E, Dest);
- }
-
- /// Copy the range [I, E) onto the uninitialized memory
- /// starting with "Dest", constructing elements into it as needed.
- template <typename T1, typename T2>
- static void uninitialized_copy(
- T1 *I, T1 *E, T2 *Dest,
- std::enable_if_t<std::is_same<std::remove_const_t<T1>, T2>::value> * =
- nullptr) {
- // Use memcpy for PODs iterated by pointers (which includes SmallVector
- // iterators): std::uninitialized_copy optimizes to memmove, but we can
- // use memcpy here. Note that I and E are iterators and thus might be
- // invalid for memcpy if they are equal.
- if (I != E)
- std::memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T));
+ if constexpr (std::is_pointer_v<It1> && std::is_pointer_v<It2> &&
+ std::is_same_v<
+ std::remove_const_t<std::remove_pointer_t<It1>>,
+ std::remove_pointer_t<It2>>) {
+ // Use memcpy for PODs iterated by pointers (which includes SmallVector
+ // iterators): std::uninitialized_copy optimizes to memmove, but we can
+ // use memcpy here. Note that I and E are iterators and thus might be
+ // invalid for memcpy if they are equal.
+ if (I != E)
+ std::memcpy(reinterpret_cast<void *>(Dest), I, (E - I) * sizeof(T));
+ } else {
+ // Arbitrary iterator types; just use the basic implementation.
+ std::uninitialized_copy(I, E, Dest);
+ }
}
/// Double the size of the allocated memory, guaranteeing space for at
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tgymnich
approved these changes
Sep 28, 2025
kuhar
reviewed
Sep 28, 2025
kuhar
approved these changes
Sep 30, 2025
kazutakahirata
deleted the
cleanup_20250927_ADT_SmallVector_uninitialized_copy
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/95/builds/18527 Here is the relevant piece of the build log for the reference |
mahesh-attarde
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Oct 3, 2025
This patch consolidates two implementations of uninitialized_copy into a single template function.
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This patch consolidates two implementations of uninitialized_copy into
a single template function.