Cut down unnecessary zero'ing when value-initializing arrays of C++ objects.

-C++ objects with user-declared constructor don't need zero'ing.
-We can zero-initialize arrays of C++ objects in "bulk" now, in which case don't zero-initialize each object again.

llvm-svn: 130453

1 files changed, 3 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 94f95053425..2f3e4680a79 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -370,8 +370,9 @@ CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
   
   // If we require zero initialization before (or instead of) calling the
   // constructor, as can be the case with a non-user-provided default
-  // constructor, emit the zero initialization now.
-  if (E->requiresZeroInitialization())
+  // constructor, emit the zero initialization now, unless destination is
+  // already zeroed.
+  if (E->requiresZeroInitialization() && !Dest.isZeroed())
     EmitNullInitialization(Dest.getAddr(), E->getType());
   
   // If this is a call to a trivial default constructor, do nothing.