Fix -Wredundant-move warning.

Without DR1579 implemented, the only case for -Wredundant-move is for a
parameter being returned with the same type as the function return type.  Also
include a check to verify that the move constructor will be used by matching
nodes in the AST dump.

llvm-svn: 243594

1 files changed, 3 insertions, 30 deletions

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index f66bc7f37ad..adec512693f 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -5944,24 +5944,6 @@ static void CheckMoveOnConstruction(Sema &S, const Expr *InitExpr,
       return;
 
     InitExpr = CCE->getArg(0)->IgnoreImpCasts();
-
-    // Remove implicit temporary and constructor nodes.
-    if (const MaterializeTemporaryExpr *MTE =
-            dyn_cast<MaterializeTemporaryExpr>(InitExpr)) {
-      InitExpr = MTE->GetTemporaryExpr()->IgnoreImpCasts();
-      while (const CXXConstructExpr *CCE =
-                 dyn_cast<CXXConstructExpr>(InitExpr)) {
-        if (isa<CXXTemporaryObjectExpr>(CCE))
-          return;
-        if (CCE->getNumArgs() == 0)
-          return;
-        if (CCE->getNumArgs() > 1 && !isa<CXXDefaultArgExpr>(CCE->getArg(1)))
-          return;
-        InitExpr = CCE->getArg(0);
-      }
-      InitExpr = InitExpr->IgnoreImpCasts();
-      DiagID = diag::warn_redundant_move_on_return;
-    }
   }
 
   // Find the std::move call and get the argument.
@@ -5991,24 +5973,15 @@ static void CheckMoveOnConstruction(Sema &S, const Expr *InitExpr,
       return;
 
     if (!S.Context.hasSameUnqualifiedType(DestType, SourceType)) {
-      if (CXXRecordDecl *RD = SourceType->getAsCXXRecordDecl()) {
-        for (auto* Construct : RD->ctors()) {
-          if (Construct->isCopyConstructor() && Construct->isDeleted())
-            return;
-        }
-      }
+      return;
     }
 
     // If we're returning a function parameter, copy elision
     // is not possible.
     if (isa<ParmVarDecl>(VD))
       DiagID = diag::warn_redundant_move_on_return;
-
-    if (DiagID == 0) {
-      DiagID = S.Context.hasSameUnqualifiedType(DestType, VD->getType())
-                   ? diag::warn_pessimizing_move_on_return
-                   : diag::warn_redundant_move_on_return;
-    }
+    else
+      DiagID = diag::warn_pessimizing_move_on_return;
   } else {
     DiagID = diag::warn_pessimizing_move_on_initialization;
     const Expr *ArgStripped = Arg->IgnoreImplicit()->IgnoreParens();