Add back testcases with updated checks

Author: KaiYG

clang/test/AST/ast-dump-stmt.c

@@ -399,4 +399,14 @@ void TestMiscStmts(void) {
   // CHECK-NEXT: IntegerLiteral 0x{{[^ ]*}} <col:13> 'int' 10
   // CHECK-NEXT: ImplicitCastExpr
   // CHECK-NEXT: DeclRefExpr 0x{{[^ ]*}} <col:17> 'int' lvalue Var 0x{{[^ ]*}} 'a' 'int'
+  ({int a = 10; a;;; });
+  // CHECK-NEXT: StmtExpr 0x{{[^ ]*}} <line:[[@LINE-1]]:3, col:23> 'void'
+  // CHECK-NEXT: CompoundStmt
+  // CHECK-NEXT: DeclStmt
+  // CHECK-NEXT: VarDecl 0x{{[^ ]*}} <col:5, col:13> col:9 used a 'int' cinit
+  // CHECK-NEXT: IntegerLiteral 0x{{[^ ]*}} <col:13> 'int' 10
+  // CHECK-NEXT: ImplicitCastExpr
+  // CHECK-NEXT: DeclRefExpr 0x{{[^ ]*}} <col:17> 'int' lvalue Var 0x{{[^ ]*}} 'a' 'int'
+  // CHECK-NEXT: NullStmt
+  // CHECK-NEXT: NullStmt
 }

clang/test/CodeGen/exprs.c

@@ -193,3 +193,20 @@ void f18(void) {
 }
 // CHECK-LABEL: define{{.*}} void @f18()
 // CHECK: call i32 @returns_int()
+
+// Ensure the right stmt is returned
+int f19(void) {
+  return ({ 3;;4; });
+}
+// CHECK-LABEL: define{{.*}} i32 @f19()
+// CHECK: [[T:%.*]] = alloca i32
+// CHECK: store i32 4, ptr [[T]]
+// CHECK: [[L:%.*]] = load i32, ptr [[T]]
+// CHECK: ret i32 [[L]]
+
+// PR166036: The trailing NullStmt should result in a void.
+void f20(void) {
+  return ({ 3;;4;; });
+}
+// CHECK-LABEL: define{{.*}} void @f20()
+// CHECK: ret void

clang/test/Sema/statements.c

@@ -118,3 +118,22 @@ void test_pr22849(void) {
     SIZE = sizeof(({unsigned long __ptr; __ptr;}))
   };
 }
+
+// Empty statements at the end of compound expressions have a result type 'void'.
+void test13(void) {
+  int a;
+  a = ({ 1; });
+  a = ({ 1; 2; }); // expected-warning {{expression result unused}}
+  a = ({ 1;; }); // expected-error {{assigning to 'int' from incompatible type 'void'}}
+                 // expected-warning@-1 {{expression result unused}}
+  a = ({int x = 1; (void)x; }); // expected-error {{assigning to 'int' from incompatible type 'void'}}
+  a = ({int x = 1;; }); // expected-error {{assigning to 'int' from incompatible type 'void'}}
+}
+
+void test14(void) { return ({}); }
+void test15(void) {
+  return ({;;;; });
+}
+void test16(void) {
+  return ({test:;; });
+}

clang/test/SemaCXX/statements.cpp

@@ -38,6 +38,34 @@ void test5() {
 struct MMX_t {};
 void test6() { __asm__("" : "=m"(*(MMX_t *)0)); }
 
+template <typename T>
+T test7(T v) {
+  return ({ // expected-warning{{use of GNU statement expression extension}}
+    T a = v;
+    a;
+  });
+}
+
+void test8() {
+  int a = test7(1);
+  double b = test7(2.0);
+}
+
+template <typename T>
+T test9(T v) {
+  return ({ // expected-warning {{use of GNU statement expression extension}}
+    T a = v;
+    a; // expected-warning {{expression result unused}}
+    ;
+    ;
+  });
+}
+
+void test10() {
+  int a = test9(1);  // expected-note {{in instantiation of function template specialization 'test9<int>' requested here}}
+  // expected-error@-10 {{cannot initialize return object of type 'int' with an rvalue of type 'void'}}
+}
+
 namespace GH48405 {
 void foo() {
   struct S {