CodeGen: FieldMemcpyizer didn't handle copies starting inside bitfields
It's possible to construct cases where the first field we are trying to
copy is in the middle of an IR field. In some complicated cases, we
would fail to use an appropriate offset inside the object. Earlier
builds of clang seemed to miscompile the code by copying an insufficient
number of bytes. Up until now, we would assert: the copying offset was
insufficiently aligned.
This fixes PR21232.
llvm-svn: 219524
diff --git a/clang/test/CodeGenCXX/pod-member-memcpys.cpp b/clang/test/CodeGenCXX/pod-member-memcpys.cpp
index 31d774c..5bd8adf 100644
--- a/clang/test/CodeGenCXX/pod-member-memcpys.cpp
+++ b/clang/test/CodeGenCXX/pod-member-memcpys.cpp
@@ -67,6 +67,13 @@
NonPOD np;
};
+struct BitfieldMember3 {
+ virtual void f();
+ int : 8;
+ int x : 1;
+ int y;
+};
+
struct InnerClassMember {
struct {
int a, b, c, d;
@@ -174,6 +181,7 @@
CALL_CC(PackedMembers)
CALL_CC(BitfieldMember2)
+CALL_CC(BitfieldMember3)
CALL_CC(ReferenceMember)
CALL_CC(InnerClassMember)
CALL_CC(BitfieldMember)
@@ -243,6 +251,11 @@
// CHECK: call void @llvm.memcpy.p0i8.p0i8.i64({{.*}}i64 16, i32 8{{.*}})
// CHECK: ret void
+// BitfieldMember3 copy-constructor:
+// CHECK-LABEL: define linkonce_odr void @_ZN15BitfieldMember3C2ERKS_(%struct.BitfieldMember3* %this, %struct.BitfieldMember3* dereferenceable({{[0-9]+}}))
+// CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %3, i8* %4, i64 8, i32 8, i1 false)
+// CHECK: ret void
+
// BitfieldMember2 copy-constructor:
// CHECK-2-LABEL: define linkonce_odr void @_ZN15BitfieldMember2C2ERKS_(%struct.BitfieldMember2* %this, %struct.BitfieldMember2* dereferenceable({{[0-9]+}}))
// CHECK-2: call void @llvm.memcpy.p0i8.p0i8.i64({{.*}}i64 16, i32 4, i1 false)