Fix: Changed parameter to const reference instead of pass-by-value

[arrowten]

No description provided.

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[llvmbot]

@llvm/pr-subscribers-debuginfo

@llvm/pr-subscribers-llvm-ir

Author: None (arrowten)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/150928.diff

2 Files Affected:

• (modified) llvm/include/llvm/IR/Metadata.h (+1-1)
• (modified) llvm/unittests/IR/MetadataTest.cpp (+25)

diff --git a/llvm/include/llvm/IR/Metadata.h b/llvm/include/llvm/IR/Metadata.h
index af252aa24567a..9cd8533069c21 100644
--- a/llvm/include/llvm/IR/Metadata.h
+++ b/llvm/include/llvm/IR/Metadata.h
@@ -237,7 +237,7 @@ class DebugValueUser {
   /// `resetDebugValue(Idx, NewDebugValue)` should be used instead.
   LLVM_ABI void handleChangedValue(void *Old, Metadata *NewDebugValue);
   DebugValueUser() = default;
-  explicit DebugValueUser(std::array<Metadata *, 3> DebugValues)
+  explicit DebugValueUser(const std::array<Metadata *, 3> &DebugValues)
       : DebugValues(DebugValues) {
     trackDebugValues();
   }
diff --git a/llvm/unittests/IR/MetadataTest.cpp b/llvm/unittests/IR/MetadataTest.cpp
index ba8367f4a396e..0e8e0831ac9d6 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -5497,4 +5497,29 @@ TEST_F(MDTupleAllocationDeathTest, ResizeRejected) {
 }
 #endif
 
+typedef MetadataTest DebugValueUserTest;
+
+namespace {
+struct DebugValueUserTestHelper: public llvm::DebugValueUser {
+  using llvm::DebugValueUser::DebugValueUser;
+  using llvm::DebugValueUser::getDebugValues;
+};
+}
+
+TEST_F(DebugValueUserTest, GetDebugValues) {
+  auto *V = getConstantAsMetadata();
+  auto *V2 = getConstantAsMetadata();
+  auto *V3 = getConstantAsMetadata();
+  std::array<Metadata *, 3> Debugs = {V, V2, V3};
+  DebugValueUserTestHelper User(Debugs);
+  ArrayRef<Metadata *> Result = User.getDebugValues();
+
+  // Verify the size of the returned array is correct,
+  // and each element is correctly stored and returned.
+  EXPECT_EQ(Result.size(), 3u);
+  EXPECT_EQ(Result[0], V);
+  EXPECT_EQ(Result[1], V2);
+  EXPECT_EQ(Result[2], V3);
+}
+
 } // end namespace

[dcb314]

Hello there, Trivial one line change looks good to me. Regards David Binderman

…

________________________________ From: Yanzuo Liu ***@***.***> Sent: 03 September 2025 00:50 To: llvm/llvm-project ***@***.***> Cc: dcb314 ***@***.***>; Review requested ***@***.***> Subject: Re: [llvm/llvm-project] Fix: Changed parameter to const reference instead of pass-by-value (PR #150928) @zwuis<https://github.com/zwuis> requested your review on: #150928<#150928> Fix: Changed parameter to const reference instead of pass-by-value. — Reply to this email directly, view it on GitHub<#150928 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ABAQX5K2YGQH7PIMQIWQJO33QY3NDAVCNFSM6AAAAACCQUYCUOVHI2DSMVQWIX3LMV45UABCJFZXG5LFIV3GK3TUJZXXI2LGNFRWC5DJN5XDWMJZGQ3TCMZUGAYDKMQ>. You are receiving this because your review was requested.Message ID: ***@***.***>

[arrowten]

@dcb314 Well thank you for that, but who accepts the PR?

[qcolombet]

Since this is touching debug related stuff, tentatively adding @adrian-prantl for review.

[adrian-prantl]

Can you explain the motivation behind this change?
We usually prefer pass-by-value for anything small enough to fit into registers.

[zwuis]

Please mention the issue fixed by this patch in PR description.