[Sema] Suppress additional warnings for C's zero initializer

Summary:
D28148 relaxed some checks for assigning { 0 } to a structure for all C
standards, but it failed to handle structures with non-integer
subobjects. Relax -Wmissing-braces checks for such structures, and add
some additional tests.

This fixes PR39931.

Patch By: al3xtjames

Reviewed By: Lekensteyn

Differential Revision: https://reviews.llvm.org/D61838

llvm-svn: 366163

1 files changed, 2 insertions, 2 deletions

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index f8017bb7ade..10ab2bf72b7 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -2303,11 +2303,11 @@ bool InitListExpr::isTransparent() const {
 bool InitListExpr::isIdiomaticZeroInitializer(const LangOptions &LangOpts) const {
   assert(isSyntacticForm() && "only test syntactic form as zero initializer");
 
-  if (LangOpts.CPlusPlus || getNumInits() != 1) {
+  if (LangOpts.CPlusPlus || getNumInits() != 1 || !getInit(0)) {
     return false;
   }
 
-  const IntegerLiteral *Lit = dyn_cast<IntegerLiteral>(getInit(0));
+  const IntegerLiteral *Lit = dyn_cast<IntegerLiteral>(getInit(0)->IgnoreImplicit());
   return Lit && Lit->getValue() == 0;
 }