diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index d755626f795d5..3d9774d5c7ff2 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -472,6 +472,8 @@ Improvements to Clang's diagnostics
 - Clang now emits ``-Wconstant-logical-operand`` warning even when constant logical
   operand is on left side.
   (`#37919 <https://github.com/llvm/llvm-project/issues/37919>`_)
+- Clang contexpr evaluator now displays notes as well as an error when a constructor
+  of a base class is not called in the constructor of its derived class.
 
 Bug Fixes in This Version
 -------------------------
diff --git a/clang/include/clang/Basic/DiagnosticASTKinds.td b/clang/include/clang/Basic/DiagnosticASTKinds.td
index 566cdc3406058..0794ed7ba6837 100644
--- a/clang/include/clang/Basic/DiagnosticASTKinds.td
+++ b/clang/include/clang/Basic/DiagnosticASTKinds.td
@@ -70,6 +70,8 @@ def note_consteval_address_accessible : Note<
   "is not a constant expression">;
 def note_constexpr_uninitialized : Note<
   "subobject %0 is not initialized">;
+def note_constexpr_uninitialized_base : Note<
+  "constructor of base class %0 is not called">;
 def note_constexpr_static_local : Note<
   "control flows through the definition of a %select{static|thread_local}0 variable">;
 def note_constexpr_subobject_declared_here : Note<
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 2f2f4eef852fd..f1bad0c7f7f22 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -2418,9 +2418,16 @@ static bool CheckEvaluationResult(CheckEvaluationResultKind CERK,
     if (const CXXRecordDecl *CD = dyn_cast<CXXRecordDecl>(RD)) {
       unsigned BaseIndex = 0;
       for (const CXXBaseSpecifier &BS : CD->bases()) {
-        if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(),
-                                   Value.getStructBase(BaseIndex), Kind,
-                                   /*SubobjectDecl=*/nullptr, CheckedTemps))
+        const APValue &BaseValue = Value.getStructBase(BaseIndex);
+        if (!BaseValue.hasValue()) {
+          SourceLocation TypeBeginLoc = BS.getBaseTypeLoc();
+          Info.FFDiag(TypeBeginLoc, diag::note_constexpr_uninitialized_base)
+              << BS.getType() << SourceRange(TypeBeginLoc, BS.getEndLoc());
+          return false;
+        }
+        if (!CheckEvaluationResult(CERK, Info, DiagLoc, BS.getType(), BaseValue,
+                                   Kind, /*SubobjectDecl=*/nullptr,
+                                   CheckedTemps))
           return false;
         ++BaseIndex;
       }
diff --git a/clang/test/Misc/constexpr-subobj-init-source-ranges.cpp b/clang/test/Misc/constexpr-subobj-init-source-ranges.cpp
new file mode 100644
index 0000000000000..342da2d886668
--- /dev/null
+++ b/clang/test/Misc/constexpr-subobj-init-source-ranges.cpp
@@ -0,0 +1,11 @@
+// RUN: not %clang_cc1 -fsyntax-only -fdiagnostics-print-source-range-info %s 2>&1 | FileCheck %s --strict-whitespace
+
+struct DelBase {
+  constexpr DelBase() = delete;
+};
+
+// CHECK:      :{[[@LINE+1]]:21-[[@LINE+1]]:28}
+struct Foo : public DelBase {
+  constexpr Foo() {};
+};
+constexpr Foo f;
diff --git a/clang/test/SemaCXX/constexpr-subobj-initialization.cpp b/clang/test/SemaCXX/constexpr-subobj-initialization.cpp
new file mode 100644
index 0000000000000..cd096a9270937
--- /dev/null
+++ b/clang/test/SemaCXX/constexpr-subobj-initialization.cpp
@@ -0,0 +1,58 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+namespace baseclass_uninit {
+struct DelBase {
+  constexpr DelBase() = delete; // expected-note {{'DelBase' has been explicitly marked deleted here}}
+};
+
+struct Foo : DelBase {  // expected-note 2{{constructor of base class 'DelBase' is not called}}
+  constexpr Foo() {}; // expected-error {{call to deleted constructor of 'DelBase'}}
+};
+constexpr Foo f; // expected-error {{must be initialized by a constant expression}}
+struct Bar : Foo {
+  constexpr Bar() {};
+};
+constexpr Bar bar; // expected-error {{must be initialized by a constant expression}}
+
+struct Base {};
+struct A : Base { // expected-note {{constructor of base class 'Base' is not called}}
+  constexpr A() : value() {} // expected-error {{member initializer 'value' does not name a non-static data member or base class}}
+};
+
+constexpr A a; // expected-error {{must be initialized by a constant expression}}
+
+struct B : Base { // expected-note {{constructor of base class 'Base' is not called}}
+  constexpr B() : {} // expected-error {{expected class member or base class name}}
+};
+
+constexpr B b; // expected-error {{must be initialized by a constant expression}}
+} // namespace baseclass_uninit
+
+
+struct Foo {
+  constexpr Foo(); // expected-note 2{{declared here}}
+};
+
+constexpr Foo ff; // expected-error {{must be initialized by a constant expression}} \
+                  // expected-note {{undefined constructor 'Foo' cannot be used in a constant expression}}
+
+struct Bar : protected Foo {
+  int i;
+  constexpr Bar() : i(12) {} // expected-note {{undefined constructor 'Foo' cannot be used in a constant expression}}
+};
+
+constexpr Bar bb; // expected-error {{must be initialized by a constant expression}} \
+                  // expected-note {{in call to 'Bar()'}}
+
+template <typename Ty>
+struct Baz {
+  constexpr Baz(); // expected-note {{declared here}}
+};
+
+struct Quux : Baz<Foo>, private Bar {
+  int i;
+  constexpr Quux() : i(12) {} // expected-note {{undefined constructor 'Baz' cannot be used in a constant expression}}
+};
+
+constexpr Quux qx; // expected-error {{must be initialized by a constant expression}} \
+                   // expected-note {{in call to 'Quux()'}}