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[ADT] Add sum_of and product_of accumulate wrappers #162129

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merged 2 commits into from
Oct 7, 2025
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[ADT] Add sum_of and product_of accumulate wrappers #162129

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[ADT] Add `sum_of` and `product_of` accumulate wrappers.
kuhar Oct 6, 2025
4b01850
Add test case
kuhar Oct 6, 2025
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22 changes: 22 additions & 0 deletions llvm/include/llvm/ADT/STLExtras.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1692,6 +1692,28 @@ template <typename R, typename E> auto accumulate(R &&Range, E &&Init) {
std::forward<E>(Init));
}

/// Wrapper for std::accumulate with a binary operator.
template <typename R, typename E, typename BinaryOp>
auto accumulate(R &&Range, E &&Init, BinaryOp &&Op) {
return std::accumulate(adl_begin(Range), adl_end(Range),
std::forward<E>(Init), std::forward<BinaryOp>(Op));
}

/// Returns the sum of all values in `Range` with `Init` initial value.
/// The default initial value is 0.
template <typename R, typename E = detail::ValueOfRange<R>>
auto sum_of(R &&Range, E Init = E{0}) {
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nit: why not just sum and product?

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We could do that but I didn't want to hijack shorter names that may already be used elsewhere... The worry is that we could have a name collision with any local function that named sum or product that takes a range.

return accumulate(std::forward<R>(Range), std::move(Init));
}

/// Returns the product of all values in `Range` with `Init` initial value.
/// The default initial value is 1.
template <typename R, typename E = detail::ValueOfRange<R>>
auto product_of(R &&Range, E Init = E{1}) {
return accumulate(std::forward<R>(Range), std::move(Init),
std::multiplies<>{});
}

/// Provide wrappers to std::for_each which take ranges instead of having to
/// pass begin/end explicitly.
template <typename R, typename UnaryFunction>
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39 changes: 39 additions & 0 deletions llvm/unittests/ADT/STLExtrasTest.cpp
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Expand Up @@ -14,6 +14,7 @@
#include <array>
#include <climits>
#include <cstddef>
#include <functional>
#include <initializer_list>
#include <iterator>
#include <list>
Expand Down Expand Up @@ -1658,6 +1659,44 @@ TEST(STLExtrasTest, Accumulate) {
EXPECT_EQ(accumulate(V1, 10), std::accumulate(V1.begin(), V1.end(), 10));
EXPECT_EQ(accumulate(drop_begin(V1), 7),
std::accumulate(V1.begin() + 1, V1.end(), 7));

EXPECT_EQ(accumulate(V1, 2, std::multiplies<>{}), 240);
}

TEST(STLExtrasTest, SumOf) {
EXPECT_EQ(sum_of(std::vector<int>()), 0);
EXPECT_EQ(sum_of(std::vector<int>(), 1), 1);
std::vector<int> V1 = {1, 2, 3, 4, 5};
static_assert(std::is_same_v<decltype(sum_of(V1)), int>);
static_assert(std::is_same_v<decltype(sum_of(V1, 1)), int>);
EXPECT_EQ(sum_of(V1), 15);
EXPECT_EQ(sum_of(V1, 1), 16);

std::vector<float> V2 = {1.0f, 2.0f, 4.0f};
static_assert(std::is_same_v<decltype(sum_of(V2)), float>);
static_assert(std::is_same_v<decltype(sum_of(V2), 1.0f), float>);
static_assert(std::is_same_v<decltype(sum_of(V2), 1.0), double>);
EXPECT_EQ(sum_of(V2), 7.0f);
EXPECT_EQ(sum_of(V2, 1.0f), 8.0f);
}

TEST(STLExtrasTest, ProductOf) {
EXPECT_EQ(product_of(std::vector<int>()), 1);
EXPECT_EQ(product_of(std::vector<int>(), 0), 0);
EXPECT_EQ(product_of(std::vector<int>(), 1), 1);
std::vector<int> V1 = {1, 2, 3, 4, 5};
static_assert(std::is_same_v<decltype(product_of(V1)), int>);
static_assert(std::is_same_v<decltype(product_of(V1, 1)), int>);
EXPECT_EQ(product_of(V1), 120);
EXPECT_EQ(product_of(V1, 1), 120);
EXPECT_EQ(product_of(V1, 2), 240);

std::vector<float> V2 = {1.0f, 2.0f, 4.0f};
static_assert(std::is_same_v<decltype(product_of(V2)), float>);
static_assert(std::is_same_v<decltype(product_of(V2), 1.0f), float>);
static_assert(std::is_same_v<decltype(product_of(V2), 1.0), double>);
EXPECT_EQ(product_of(V2), 8.0f);
EXPECT_EQ(product_of(V2, 4.0f), 32.0f);
}

struct Foo;
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