Revert r301742 which made ExprConstant checking apply to all full-exprs.

This patch also exposed pre-existing bugs in clang, see PR32864 and PR33140#c3 .

llvm-svn: 305239

1 files changed, 23 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index b794628db73..44184c73664 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -9935,6 +9935,28 @@ void Sema::CheckBoolLikeConversion(Expr *E, SourceLocation CC) {
   ::CheckBoolLikeConversion(*this, E, CC);
 }
 
+/// Diagnose when expression is an integer constant expression and its evaluation
+/// results in integer overflow
+void Sema::CheckForIntOverflow (Expr *E) {
+  // Use a work list to deal with nested struct initializers.
+  SmallVector<Expr *, 2> Exprs(1, E);
+
+  do {
+    Expr *E = Exprs.pop_back_val();
+
+    if (isa<BinaryOperator>(E->IgnoreParenCasts())) {
+      E->IgnoreParenCasts()->EvaluateForOverflow(Context);
+      continue;
+    }
+
+    if (auto InitList = dyn_cast<InitListExpr>(E))
+      Exprs.append(InitList->inits().begin(), InitList->inits().end());
+
+    if (isa<ObjCBoxedExpr>(E))
+      E->IgnoreParenCasts()->EvaluateForOverflow(Context);
+  } while (!Exprs.empty());
+}
+
 namespace {
 /// \brief Visitor for expressions which looks for unsequenced operations on the
 /// same object.
@@ -10436,7 +10458,7 @@ void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc,
   if (!E->isInstantiationDependent())
     CheckUnsequencedOperations(E);
   if (!IsConstexpr && !E->isValueDependent())
-    E->EvaluateForOverflow(Context);
+    CheckForIntOverflow(E);
   DiagnoseMisalignedMembers();
 }