[OpenACC] Fixed error recovery during jump diagnostics for OpenACC

We didn't consider/test a case where the structured block/loop would be
empty, which happens when the body is ONLY a break.

Fixes: #140712

Author: erichkeane

clang/lib/Sema/JumpDiagnostics.cpp

@@ -602,7 +602,10 @@ void JumpScopeChecker::BuildScopeInformation(Stmt *S,
     Scopes.push_back(GotoScope(
         ParentScope, diag::note_acc_branch_into_compute_construct,
         diag::note_acc_branch_out_of_compute_construct, CC->getBeginLoc()));
-    BuildScopeInformation(CC->getStructuredBlock(), NewParentScope);
+    // This can be 'null' if the 'body' is a break that we diagnosed, so no
+    // reason to put the scope into place.
+    if (CC->getStructuredBlock())
+      BuildScopeInformation(CC->getStructuredBlock(), NewParentScope);
     return;
   }
 
@@ -612,7 +615,10 @@ void JumpScopeChecker::BuildScopeInformation(Stmt *S,
     Scopes.push_back(GotoScope(
         ParentScope, diag::note_acc_branch_into_compute_construct,
         diag::note_acc_branch_out_of_compute_construct, CC->getBeginLoc()));
-    BuildScopeInformation(CC->getLoop(), NewParentScope);
+    // This can be 'null' if the 'body' is a break that we diagnosed, so no
+    // reason to put the scope into place.
+    if (CC->getLoop())
+      BuildScopeInformation(CC->getLoop(), NewParentScope);
     return;
   }
 

clang/test/SemaOpenACC/gh140712.cpp

@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 %s -fopenacc -verify
+
+void foo() {
+  switch (int x = 0) {
+    case 0:
+#pragma acc parallel
+      break; // expected-error{{invalid branch out of OpenACC Compute/Combined Construct}}
+  }
+}