[clang] [clang][ExprConst] allow single element access of vector object to be constant expression (PR #101126)

[Vikram Hegde via cfe-commits]

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@@ -3,40 +3,40 @@
 
 typedef int __attribute__((vector_size(16))) VI4;
 constexpr VI4 A = {1,2,3,4};
-static_assert(A[0] == 1, ""); // ref-error {{not an integral constant expression}}
-static_assert(A[1] == 2, ""); // ref-error {{not an integral constant expression}}
-static_assert(A[2] == 3, ""); // ref-error {{not an integral constant expression}}
-static_assert(A[3] == 4, ""); // ref-error {{not an integral constant expression}}
+static_assert(A[0] == 1, "");
+static_assert(A[1] == 2, "");
+static_assert(A[2] == 3, "");
+static_assert(A[3] == 4, "");
 
 
 /// FIXME: It would be nice if the note said 'vector' instead of 'array'.
-static_assert(A[12] == 4, ""); // ref-error {{not an integral constant expression}} \
-                               // expected-error {{not an integral constant expression}} \
-                               // expected-note {{cannot refer to element 12 of array of 4 elements in a constant expression}}
+static_assert(A[12] == 4, ""); // both-error {{not an integral constant expression}} \
+                               // expected-note {{cannot refer to element 12 of array of 4 elements in a constant expression}} \
+                               // ref-note {{read of dereferenced one-past-the-end pointer is not allowed in a constant expression}}
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vikramRH wrote:

I just kept the original version of the PR, but the message "cannot refer to element 12 of array of 4 elements" seems correct here. I shall update this

https://github.com/llvm/llvm-project/pull/101126