Don't copy or initialize empty classes. Fixes PR7012.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@102891 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index 84841bf5b9f854cf4a6da31bdd3b18b2fbfcfe6b..96274cb6e7614e222bb6916fd72ef93cc64bfd9c 100644 (file)
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -738,6 +738,14 @@ void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
                                         bool isVolatile) {
   assert(!Ty->isAnyComplexType() && "Shouldn't happen for complex");
 
+  // Ignore empty classes in C++.
+  if (getContext().getLangOptions().CPlusPlus) {
+    if (const RecordType *RT = Ty->getAs<RecordType>()) {
+      if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty())
+        return;
+    }
+  }
+  
   // Aggregate assignment turns into llvm.memcpy.  This is almost valid per
   // C99 6.5.16.1p3, which states "If the value being stored in an object is
   // read from another object that overlaps in anyway the storage of the first

diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 34b904972f900dcac18162a59698e8022d9390d7..d3bf1645a026f1fbd8739618f3e04c932e17142d 100644 (file)
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -473,6 +473,14 @@ void CodeGenFunction::ErrorUnsupported(const Stmt *S, const char *Type,
 }
 
 void CodeGenFunction::EmitMemSetToZero(llvm::Value *DestPtr, QualType Ty) {
+  // Ignore empty classes in C++.
+  if (getContext().getLangOptions().CPlusPlus) {
+    if (const RecordType *RT = Ty->getAs<RecordType>()) {
+      if (cast<CXXRecordDecl>(RT->getDecl())->isEmpty())
+        return;
+    }
+  }
+  
   const llvm::Type *BP = llvm::Type::getInt8PtrTy(VMContext);
   if (DestPtr->getType() != BP)
     DestPtr = Builder.CreateBitCast(DestPtr, BP, "tmp");

diff --git a/test/CodeGenCXX/new.cpp b/test/CodeGenCXX/new.cpp
index ca7c52f2cc0d78164bb847290ba49e18ceb2def4..cc6288575bb52e9b489bcea442f6b73990a5da84 100644 (file)
--- a/test/CodeGenCXX/new.cpp
+++ b/test/CodeGenCXX/new.cpp
@@ -90,7 +90,7 @@ A* t10() {
   return new(1, 2, 3.45, 100) A;
 }
 
-struct B { };
+struct B { int a; };
 void t11() {
   // CHECK: call noalias i8* @_Znwm
   // CHECK: call void @llvm.memset.p0i8.i64(