Set and use Elidable in elimination of copy ctors.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@78331 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGCXX.cpp b/lib/CodeGen/CGCXX.cpp
index 567c58373cd636a5bbfafdb150f937ce8525c8b3..0d51c03bab5f5d676e2026151ced3334673dd8a6 100644 (file)
--- a/lib/CodeGen/CGCXX.cpp
+++ b/lib/CodeGen/CGCXX.cpp
@@ -258,16 +258,10 @@ CodeGenFunction::EmitCXXConstructExpr(llvm::Value *Dest,
 
   // Code gen optimization to eliminate copy constructor and return 
   // its first argument instead.
-  const CXXConstructorDecl *CDecl = E->getConstructor();
-  if (E->getNumArgs() == 1 &&
-      CDecl->isCopyConstructor(getContext())) {
+  if (E->isElidable()) {
     CXXConstructExpr::const_arg_iterator i = E->arg_begin();
-    const Expr *SubExpr = (*i);
-    // FIXME. Any other cases can be optimized away?
-    if (isa<CallExpr>(SubExpr) || isa<CXXTemporaryObjectExpr>(SubExpr)) {
-      EmitAggExpr(SubExpr, Dest, false);
-      return;
-    }
+    EmitAggExpr((*i), Dest, false);
+    return;
   }
   // Call the constructor.
   EmitCXXConstructorCall(E->getConstructor(), Ctor_Complete, Dest, 

diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 7e0422e432be14b678abde43ac062ad6ac5c97e5..5b7493819103229c1e9d2a83930902311d577fb0 100644 (file)
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -911,8 +911,10 @@ Sema::PerformImplicitConversion(Expr *&From, QualType ToType,
     assert(!ToType->isReferenceType());
     
     // FIXME: Keep track of whether the copy constructor is elidable or not.
-    From = BuildCXXConstructExpr(Context,
-                                 ToType, SCS.CopyConstructor, false, &From, 1);
+    bool Elidable = (isa<CallExpr>(From) || 
+                     isa<CXXTemporaryObjectExpr>(From));
+    From = BuildCXXConstructExpr(Context, ToType, 
+                                 SCS.CopyConstructor, Elidable, &From, 1);
     return false;
   }
 

diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index 445cd691d6ad771d7d7b2c25b7b0a601ad832618..29113822f7303cc2db9ad99205db9ebf4f0b0092 100644 (file)
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -176,9 +176,10 @@ bool Sema::CheckInitializerTypes(Expr *&Init, QualType &DeclType,
                                              DirectInit? IK_Direct : IK_Copy);
         if (!Constructor)
           return true;
-        
+        bool Elidable = (isa<CallExpr>(Init) || 
+                         isa<CXXTemporaryObjectExpr>(Init));
         Init = BuildCXXConstructExpr(Context,
-                                     DeclType, Constructor, false, &Init, 1);
+                                     DeclType, Constructor, Elidable, &Init, 1);
         Init = MaybeCreateCXXExprWithTemporaries(Init, /*DestroyTemps=*/true);
         return false;
       }