Revert 363295, it caused PR42276. Also revert follow-ups 363337, 363340.

Revert 363340 "Remove unused SK_LValueToRValue initialization step."
Revert 363337 "PR23833, DR2140: an lvalue-to-rvalue conversion on a glvalue of type"
Revert 363295 "C++ DR712 and others: handle non-odr-use resulting from an lvalue-to-rvalue conversion applied to a member access or similar not-quite-trivial lvalue expression."

llvm-svn: 363352

1 files changed, 23 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index d5ef5eddf3e..1a1d9347985 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -3282,6 +3282,7 @@ void InitializationSequence::Step::Destroy() {
   case SK_QualificationConversionXValue:
   case SK_QualificationConversionLValue:
   case SK_AtomicConversion:
+  case SK_LValueToRValue:
   case SK_ListInitialization:
   case SK_UnwrapInitList:
   case SK_RewrapInitList:
@@ -3465,6 +3466,15 @@ void InitializationSequence::AddAtomicConversionStep(QualType Ty) {
   Steps.push_back(S);
 }
 
+void InitializationSequence::AddLValueToRValueStep(QualType Ty) {
+  assert(!Ty.hasQualifiers() && "rvalues may not have qualifiers");
+
+  Step S;
+  S.Kind = SK_LValueToRValue;
+  S.Type = Ty;
+  Steps.push_back(S);
+}
+
 void InitializationSequence::AddConversionSequenceStep(
     const ImplicitConversionSequence &ICS, QualType T,
     bool TopLevelOfInitList) {
@@ -7495,6 +7505,7 @@ ExprResult InitializationSequence::Perform(Sema &S,
   case SK_QualificationConversionXValue:
   case SK_QualificationConversionRValue:
   case SK_AtomicConversion:
+  case SK_LValueToRValue:
   case SK_ConversionSequence:
   case SK_ConversionSequenceNoNarrowing:
   case SK_ListInitialization:
@@ -7766,6 +7777,14 @@ ExprResult InitializationSequence::Perform(Sema &S,
       break;
     }
 
+    case SK_LValueToRValue: {
+      assert(CurInit.get()->isGLValue() && "cannot load from a prvalue");
+      CurInit = ImplicitCastExpr::Create(S.Context, Step->Type,
+                                         CK_LValueToRValue, CurInit.get(),
+                                         /*BasePath=*/nullptr, VK_RValue);
+      break;
+    }
+
     case SK_ConversionSequence:
     case SK_ConversionSequenceNoNarrowing: {
       if (const auto *FromPtrType =
@@ -8987,6 +9006,10 @@ void InitializationSequence::dump(raw_ostream &OS) const {
       OS << "non-atomic-to-atomic conversion";
       break;
 
+    case SK_LValueToRValue:
+      OS << "load (lvalue to rvalue)";
+      break;
+
     case SK_ConversionSequence:
       OS << "implicit conversion sequence (";
       S->ICS->dump(); // FIXME: use OS