[clang][Sema] Fix type of an statement expression ending with an atomic type

clang/docs/ReleaseNotes.rst

@@ -163,6 +163,7 @@ Bug Fixes to C++ Support
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^
+- Fixed type deduction of an statement expression (a GCC extension) ending with an atomic type. (#GH106576)
 
 Miscellaneous Bug Fixes
 ^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/Sema/SemaExpr.cpp

@@ -15946,7 +15946,7 @@ ExprResult Sema::ActOnStmtExprResult(ExprResult ER) {
   // FIXME: Provide a better location for the initialization.
   return PerformCopyInitialization(
       InitializedEntity::InitializeStmtExprResult(
-          E->getBeginLoc(), E->getType().getUnqualifiedType()),
+          E->getBeginLoc(), E->getType().getAtomicUnqualifiedType()),
       SourceLocation(), E);
 }
 

clang/test/Sema/gh106576.c

@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+typedef _Atomic char atomic_char;
+
+typedef _Atomic char atomic_char;
+
+atomic_char counter;
+
+char load_plus_one(void) {
+  return ({counter;}) + 1; // no crash
+}
+
+char type_of_stmt_expr(void) {
+  typeof(({counter;})) y = ""; // expected-error-re {{incompatible pointer to integer conversion initializing 'typeof (({{{.*}}}))' (aka 'char') with an expression of type 'char[1]'}}
+  return y;
+}