diff --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp index 2e2b420740be..524697cd2302 100644 --- a/clang/lib/CodeGen/CGClass.cpp +++ b/clang/lib/CodeGen/CGClass.cpp @@ -1747,9 +1747,10 @@ void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D, "trivial 1-arg ctor not a copy/move ctor"); const Expr *Arg = E->getArg(0); - QualType Ty = Arg->getType(); + QualType SrcTy = Arg->getType(); llvm::Value *Src = EmitLValue(Arg).getAddress(); - EmitAggregateCopy(This, Src, Ty); + QualType DestTy = getContext().getTypeDeclType(D->getParent()); + EmitAggregateCopyCtor(This, Src, DestTy, SrcTy); return; } @@ -1789,7 +1790,9 @@ CodeGenFunction::EmitSynthesizedCXXCopyCtorCall(const CXXConstructorDecl *D, assert(E->getNumArgs() == 1 && "unexpected argcount for trivial ctor"); assert(D->isCopyOrMoveConstructor() && "trivial 1-arg ctor not a copy/move ctor"); - EmitAggregateCopy(This, Src, E->arg_begin()->getType()); + EmitAggregateCopyCtor(This, Src, + getContext().getTypeDeclType(D->getParent()), + E->arg_begin()->getType()); return; } llvm::Value *Callee = CGM.getAddrOfCXXStructor(D, StructorType::Complete); diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h index ea63c84d9fc6..03d2ab313fb2 100644 --- a/clang/lib/CodeGen/CodeGenFunction.h +++ b/clang/lib/CodeGen/CodeGenFunction.h @@ -1559,6 +1559,15 @@ public: true); } + void EmitAggregateCopyCtor(llvm::Value *DestPtr, llvm::Value *SrcPtr, + QualType DestTy, QualType SrcTy) { + CharUnits DestTypeAlign = getContext().getTypeAlignInChars(DestTy); + CharUnits SrcTypeAlign = getContext().getTypeAlignInChars(SrcTy); + EmitAggregateCopy(DestPtr, SrcPtr, SrcTy, /*IsVolatile=*/false, + std::min(DestTypeAlign, SrcTypeAlign), + /*IsAssignment=*/false); + } + /// EmitAggregateCopy - Emit an aggregate copy. /// /// \param isVolatile - True iff either the source or the destination is diff --git a/clang/test/CodeGenCXX/copy-constructor-elim.cpp b/clang/test/CodeGenCXX/copy-constructor-elim.cpp index 8e9bee973771..d82af28655c8 100644 --- a/clang/test/CodeGenCXX/copy-constructor-elim.cpp +++ b/clang/test/CodeGenCXX/copy-constructor-elim.cpp @@ -43,3 +43,17 @@ int main() { S s; Call(s); } + +struct V { + int x; +}; + +typedef V V_over_aligned __attribute((aligned(8))); +extern const V_over_aligned gv1 = {}; + +extern "C" V f() { return gv1; } + +// Make sure that we obey the destination's alignment requirements when emitting +// the copy. +// CHECK-LABEL: define i32 @f() +// CHECK: call void @llvm.memcpy.p0i8.p0i8.i64({{.*}}, i8* bitcast (%struct.V* @gv1 to i8*), i64 4, i32 4, i1 false)