[ADT] Simplify DenseMapInfo<std::tuple<...>> with constexpr if (NFC) #156810
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This patch consolidates two implementations of getHashValueImpl into one with "constexpr if", which should be more readable than the SFINAE-based approach. The same applies to isEqualImpl.
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@llvm/pr-subscribers-llvm-adt Author: Kazu Hirata (kazutakahirata) ChangesThis patch consolidates two implementations of getHashValueImpl into The same applies to isEqualImpl. Full diff: https://github.com/llvm/llvm-project/pull/156810.diff 1 Files Affected:
diff --git a/llvm/include/llvm/ADT/DenseMapInfo.h b/llvm/include/llvm/ADT/DenseMapInfo.h
index ec7a116856bb4..717156c4bd196 100644
--- a/llvm/include/llvm/ADT/DenseMapInfo.h
+++ b/llvm/include/llvm/ADT/DenseMapInfo.h
@@ -179,41 +179,35 @@ template <typename... Ts> struct DenseMapInfo<std::tuple<Ts...>> {
return Tuple(DenseMapInfo<Ts>::getTombstoneKey()...);
}
- template <unsigned I>
- static unsigned getHashValueImpl(const Tuple &values, std::false_type) {
- using EltType = std::tuple_element_t<I, Tuple>;
- std::integral_constant<bool, I + 1 == sizeof...(Ts)> atEnd;
- return detail::combineHashValue(
- DenseMapInfo<EltType>::getHashValue(std::get<I>(values)),
- getHashValueImpl<I + 1>(values, atEnd));
- }
-
- template <unsigned I>
- static unsigned getHashValueImpl(const Tuple &, std::true_type) {
- return 0;
+ template <unsigned I> static unsigned getHashValueImpl(const Tuple &values) {
+ if constexpr (I == sizeof...(Ts))
+ return 0;
+ else {
+ using EltType = std::tuple_element_t<I, Tuple>;
+ return detail::combineHashValue(
+ DenseMapInfo<EltType>::getHashValue(std::get<I>(values)),
+ getHashValueImpl<I + 1>(values));
+ }
}
static unsigned getHashValue(const std::tuple<Ts...> &values) {
- std::integral_constant<bool, 0 == sizeof...(Ts)> atEnd;
- return getHashValueImpl<0>(values, atEnd);
+ return getHashValueImpl<0>(values);
}
template <unsigned I>
- static bool isEqualImpl(const Tuple &lhs, const Tuple &rhs, std::false_type) {
- using EltType = std::tuple_element_t<I, Tuple>;
- std::integral_constant<bool, I + 1 == sizeof...(Ts)> atEnd;
- return DenseMapInfo<EltType>::isEqual(std::get<I>(lhs), std::get<I>(rhs)) &&
- isEqualImpl<I + 1>(lhs, rhs, atEnd);
- }
-
- template <unsigned I>
- static bool isEqualImpl(const Tuple &, const Tuple &, std::true_type) {
- return true;
+ static bool isEqualImpl(const Tuple &lhs, const Tuple &rhs) {
+ if constexpr (I == sizeof...(Ts))
+ return true;
+ else {
+ using EltType = std::tuple_element_t<I, Tuple>;
+ return DenseMapInfo<EltType>::isEqual(std::get<I>(lhs),
+ std::get<I>(rhs)) &&
+ isEqualImpl<I + 1>(lhs, rhs);
+ }
}
static bool isEqual(const Tuple &lhs, const Tuple &rhs) {
- std::integral_constant<bool, 0 == sizeof...(Ts)> atEnd;
- return isEqualImpl<0>(lhs, rhs, atEnd);
+ return isEqualImpl<0>(lhs, rhs);
}
};
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tgymnich
approved these changes
Sep 4, 2025
kuhar
reviewed
Sep 4, 2025
kazutakahirata
added a commit
to kazutakahirata/llvm-project
that referenced
this pull request
Sep 4, 2025
This is a follow-up for llvm#156810.
kazutakahirata
added a commit
that referenced
this pull request
Sep 4, 2025
This is a follow-up for #156810.
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This patch consolidates two implementations of getHashValueImpl into
one with "constexpr if", which should be more readable than the
SFINAE-based approach.
The same applies to isEqualImpl.