commit feaa5aa840dcda69bd4133536142be882f696114
author Akira Hatanaka <ahatanak@gmail.com> Thu Apr 24 08:47:29 2025 -0700
committer GitHub <noreply@github.com> Thu Apr 24 08:47:29 2025 -0700
tree 10772e9b14fa6e7074369684f03d941093fb4829
parent 2ca071b1decf006a31385c75478b57013964e49a

Fix a crash in constant evaluation of ExtVectorElementExprs (#136771)

Handle the case where the base expression is a pointer to a vector type.

rdar://149223362

clang/lib/AST/ExprConstant.cpp

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 7c933f4..f2e49b9 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -9202,7 +9202,10 @@
 
   if (Success) {
     Result.setFrom(Info.Ctx, Val);
-    const auto *VT = E->getBase()->getType()->castAs<VectorType>();
+    QualType BaseType = E->getBase()->getType();
+    if (E->isArrow())
+      BaseType = BaseType->getPointeeType();
+    const auto *VT = BaseType->castAs<VectorType>();
     HandleLValueVectorElement(Info, E, Result, VT->getElementType(),
                               VT->getNumElements(), Indices[0]);
   }

clang/test/SemaCXX/constexpr-vectors-access-elements.cpp

diff --git a/clang/test/SemaCXX/constexpr-vectors-access-elements.cpp b/clang/test/SemaCXX/constexpr-vectors-access-elements.cpp
index 08223e1..58efcde 100644
--- a/clang/test/SemaCXX/constexpr-vectors-access-elements.cpp
+++ b/clang/test/SemaCXX/constexpr-vectors-access-elements.cpp
@@ -43,4 +43,6 @@
 // make sure clang rejects taking address of a vector element
 static_assert(&b[1]); // expected-error {{address of vector element requested}}
 
+constexpr const FourIntsExtVec *p = &b;
+static_assert(p->x == 1);
 }