Introduce a new cast kind for an "lvalue bitcast", which handles
reinterpret_casts (possibly indirectly via C-style/functional casts)
on values, e.g.,
int i;
reinterpret_cast<short&>(i);
The IR generated for this is essentially the same as for
*reinterpret_cast<short*>(&i).
Fixes PR6437, PR7593, and PR7344.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@108294 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 0426a60..5a4808b 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1816,7 +1816,8 @@
return LValue::MakeAddr(Derived, MakeQualifiers(E->getType()));
}
- case CastExpr::CK_BitCast: {
+ case CastExpr::CK_BitCast:
+ case CastExpr::CK_LValueBitCast: {
// This must be a reinterpret_cast (or c-style equivalent).
const ExplicitCastExpr *CE = cast<ExplicitCastExpr>(E);
diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index 20722f7..219a5f9 100644
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -307,6 +307,10 @@
break;
}
+ case CastExpr::CK_LValueBitCast:
+ llvm_unreachable("there are no lvalue bit-casts on aggregates");
+ break;
+
case CastExpr::CK_BitCast: {
// This must be a member function pointer cast.
Visit(E->getSubExpr());
diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index 1ebc2c5..ef38209 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -925,6 +925,15 @@
//assert(0 && "Unknown cast kind!");
break;
+ case CastExpr::CK_LValueBitCast: {
+ Value *V = EmitLValue(E).getAddress();
+ V = Builder.CreateBitCast(V,
+ ConvertType(CGF.getContext().getPointerType(DestTy)));
+ // FIXME: Are the qualifiers correct here?
+ return EmitLoadOfLValue(LValue::MakeAddr(V, CGF.MakeQualifiers(DestTy)),
+ DestTy);
+ }
+
case CastExpr::CK_AnyPointerToObjCPointerCast:
case CastExpr::CK_AnyPointerToBlockPointerCast:
case CastExpr::CK_BitCast: {