diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2719,6 +2719,8 @@
   "use of this statement in a constexpr %select{function|constructor}0 "
   "is incompatible with C++ standards before C++2b">,
   InGroup<CXXPre2bCompat>, DefaultIgnore;
+def err_constexpr_body_invalid_omp_simd_stmt_with_clauses : Error<
+  "OpenMP simd statement with clauses not allowed in %select{constexpr|consteval}1 %select{function|constructor}0">;
 def ext_constexpr_type_definition : ExtWarn<
   "type definition in a constexpr %select{function|constructor}0 "
   "is a C++14 extension">, InGroup<CXX14>;
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -5489,6 +5489,13 @@
   case Stmt::CXXTryStmtClass:
     // Evaluate try blocks by evaluating all sub statements.
     return EvaluateStmt(Result, Info, cast<CXXTryStmt>(S)->getTryBlock(), Case);
+
+  case Stmt::OMPSimdDirectiveClass: {
+    const Stmt *LoopStmt = cast<OMPSimdDirective>(S)->getAssociatedStmt();
+    if (auto *CS = dyn_cast<CapturedStmt>(LoopStmt))
+      LoopStmt = CS->getCapturedStmt();
+    return EvaluateStmt(Result, Info, LoopStmt, Case);
+  }
   }
 }
 
@@ -8271,7 +8278,8 @@
     // variable) or be ill-formed (and trigger an appropriate evaluation
     // diagnostic)).
     CallStackFrame *CurrFrame = Info.CurrentCall;
-    if (CurrFrame->Callee && CurrFrame->Callee->Equals(VD->getDeclContext())) {
+    if (CurrFrame->Callee &&
+        CurrFrame->Callee->Encloses(VD->getDeclContext())) {
       // Function parameters are stored in some caller's frame. (Usually the
       // immediate caller, but for an inherited constructor they may be more
       // distant.)
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -2169,6 +2169,23 @@
       return false;
     return true;
 
+  case Stmt::OMPSimdDirectiveClass: {
+    if (!cast<OMPSimdDirective>(S)->clauses().empty()) {
+      if (Kind == Sema::CheckConstexprKind::Diagnose) {
+        SemaRef.Diag(
+            S->getBeginLoc(),
+            diag::err_constexpr_body_invalid_omp_simd_stmt_with_clauses)
+            << isa<CXXConstructorDecl>(Dcl) << Dcl->isConsteval();
+      }
+      return false;
+    }
+    Stmt *LoopStmt = cast<OMPSimdDirective>(S)->getAssociatedStmt();
+    if (auto *CS = dyn_cast<CapturedStmt>(LoopStmt))
+      LoopStmt = CS->getCapturedStmt();
+    return CheckConstexprFunctionStmt(SemaRef, Dcl, LoopStmt, ReturnStmts,
+                                      Cxx1yLoc, Cxx2aLoc, Cxx2bLoc, Kind);
+  }
+
   default:
     if (!isa<Expr>(S))
       break;
diff --git a/clang/test/SemaCXX/constexpr-openmp-simd.cpp b/clang/test/SemaCXX/constexpr-openmp-simd.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/SemaCXX/constexpr-openmp-simd.cpp
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -verify -std=c++2a -fsyntax-only -fopenmp -triple x86_64-apple-macosx10.14.0 %s
+// RUN: %clang_cc1 -verify -std=c++2a -fsyntax-only -fopenmp -triple x86_64-apple-macosx10.14.0 %s -fno-signed-char
+// RUN: %clang_cc1 -verify -std=c++2a -fsyntax-only -fopenmp -triple aarch64_be-linux-gnu %s
+// RUN: %clang_cc1 -emit-llvm -std=c++2a -fopenmp -triple aarch64_be-linux-gnu %s -DEMIT_IR -o - | FileCheck %s
+
+constexpr int good(int r) {
+
+  #pragma omp simd
+  for (int i = 0; i != 10; ++i)
+    r += 1;
+
+  return r;
+}
+
+int test1() {
+  if (good(10) == 20)
+    return 42;
+  return good(7);
+// Make sure this is folded to 42 and not 17.
+// CHECK: ret i32 42
+}
+
+#ifndef EMIT_IR
+constexpr int bad(int r) {
+  #pragma omp simd private(r) // expected-error {{OpenMP simd statement with clauses not allowed in constexpr function}}
+  for (int i = 0; i != 10; ++i)
+    r += 1;
+
+  return r;
+}
+
+int test2() {
+  return bad(10);
+}
+#endif