diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 73aaaad8b32e5..9b02a5b923386 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -495,6 +495,8 @@ Bug Fixes to C++ Support
   nontrivial member when another member has an initializer. (#GH81774)
 - Fixed a template depth issue when parsing lambdas inside a type constraint. (#GH162092)
 - Diagnose unresolved overload sets in non-dependent compound requirements. (#GH51246) (#GH97753)
+- Fixed a crash that occurred when a static constexpr data member of a class
+  template was declared with an incomplete type. (#GH120371)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index fc3aabf5741ca..db9e4ac4b7897 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -14933,7 +14933,7 @@ void Sema::CheckCompleteVariableDeclaration(VarDecl *var) {
 
   // Apply section attributes and pragmas to global variables.
   if (GlobalStorage && var->isThisDeclarationADefinition() &&
-      !inTemplateInstantiation()) {
+      !var->getDeclContext()->isDependentContext()) {
     PragmaStack<StringLiteral *> *Stack = nullptr;
     int SectionFlags = ASTContext::PSF_Read;
     bool MSVCEnv =
diff --git a/clang/test/SemaCXX/attr-section.cpp b/clang/test/SemaCXX/attr-section.cpp
index 1c07e3dd8bba2..6ed432f1cf7e0 100644
--- a/clang/test/SemaCXX/attr-section.cpp
+++ b/clang/test/SemaCXX/attr-section.cpp
@@ -65,7 +65,30 @@ struct t1 {
   constexpr t1(int) { }
 };
 extern const t1 v1;
-__attribute__((section("non_trivial_ctor"))) const t1 v1; // expected-note {{declared here}}
+__attribute__((section("non_trivial_ctor"))) const t1 v1; // expected-note 2 {{declared here}}
 extern const t1 v2;
 __attribute__((section("non_trivial_ctor"))) const t1 v2{3}; // expected-error {{'v2' causes a section type conflict with 'v1'}}
 } // namespace non_trivial_ctor
+
+namespace dependent_context {
+template <class T>
+struct A {
+  struct B;
+  static constexpr B b{nullptr}; // This used to crash.
+};
+
+struct B1 { void *p; };
+template <class T>
+struct A1 {
+  __attribute__((section("non_trivial_ctor")))
+  static constexpr B1 b{nullptr}; // no diagnostic expected
+};
+
+template <class T>
+struct C {
+  __attribute__((section("non_trivial_ctor")))
+  static constexpr int m{123}; // expected-error {{'m' causes a section type conflict with 'v1'}}
+};
+
+auto *p = &C<int>::m; // expected-note {{in instantiation of static data member 'dependent_context::C<int>::m' requested here}}
+}