[llvm][ADT] Add getSingleElement helper
#131508
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
matthias-springer
requested review from
nikic,
kuhar,
dwblaikie and
kazutakahirata
|
@llvm/pr-subscribers-llvm-adt Author: Matthias Springer (matthias-springer) ChangesThis commit adds a new helper function: This function asserts that the container has a single element and then returns that element. This helper function is useful during 1:N dialect conversions in MLIR, where certain Full diff: https://github.com/llvm/llvm-project/pull/131508.diff 2 Files Affected:
diff --git a/llvm/include/llvm/ADT/STLExtras.h b/llvm/include/llvm/ADT/STLExtras.h
index 78b7e94c2b3a1..dc0443c9244be 100644
--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -325,6 +325,14 @@ template <typename ContainerTy> bool hasSingleElement(ContainerTy &&C) {
return B != E && std::next(B) == E;
}
+/// Asserts that the given container has a single element and returns that
+/// element.
+template <typename ContainerTy>
+decltype(auto) getSingleElement(ContainerTy &&C) {
+ assert(hasSingleElement(C) && "expected container with single element");
+ return *adl_begin(C);
+}
+
/// Return a range covering \p RangeOrContainer with the first N elements
/// excluded.
template <typename T> auto drop_begin(T &&RangeOrContainer, size_t N = 1) {
diff --git a/llvm/unittests/ADT/STLExtrasTest.cpp b/llvm/unittests/ADT/STLExtrasTest.cpp
index dbb094b0a3088..df8c0a4e4819b 100644
--- a/llvm/unittests/ADT/STLExtrasTest.cpp
+++ b/llvm/unittests/ADT/STLExtrasTest.cpp
@@ -1016,6 +1016,28 @@ TEST(STLExtrasTest, hasSingleElement) {
EXPECT_FALSE(hasSingleElement(S));
}
+TEST(STLExtrasTest, getSingleElement) {
+ // Note: Asserting behavior of getSingleElement cannot be tested because the
+ // program would crash.
+ const std::vector<int> V1 = {7};
+ EXPECT_EQ(getSingleElement(V1), 7);
+
+ std::vector<int> V2 = {8};
+ EXPECT_EQ(getSingleElement(V2), 8);
+
+ SmallVector<int> V3 {9};
+ EXPECT_EQ(getSingleElement(V3), 9);
+
+ std::list<int> L1 = {10};
+ EXPECT_EQ(getSingleElement(L1), 10);
+
+ // Make sure that we use the `begin`/`end` functions from `some_namespace`,
+ // using ADL.
+ some_namespace::some_struct S;
+ S.data = V2;
+ EXPECT_EQ(getSingleElement(S), 8);
+}
+
TEST(STLExtrasTest, hasNItems) {
const std::list<int> V0 = {}, V1 = {1}, V2 = {1, 2};
const std::list<int> V3 = {1, 3, 5};
|
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
matthias-springer
force-pushed
the
users/matthias-springer/get_single_el
branch
2 times, most recently
from
75e8b95 to
65159c4
Compare
matthias-springer
force-pushed
the
users/matthias-springer/get_single_el
branch
from
65159c4 to
78eca92
Compare
kuhar
reviewed
Mar 16, 2025
kuhar
reviewed
Mar 16, 2025
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/169/builds/9489 Here is the relevant piece of the build log for the reference |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/64/builds/2511 Here is the relevant piece of the build log for the reference |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This commit adds a new helper function:
getSingleElementThis function asserts that the container has a single element and then returns that element. This helper function is useful during 1:N dialect conversions in MLIR, where certain
ValueRanges (returned from the adaptor) are known to have a single value.