r282556 - P0145R3 (C++17 evaluation order tweaks): evaluate the right-hand side of

Richard Smith via cfe-commits cfe-commits at lists.llvm.org
Tue Sep 27 16:44:23 PDT 2016


Author: rsmith
Date: Tue Sep 27 18:44:22 2016
New Revision: 282556

URL: http://llvm.org/viewvc/llvm-project?rev=282556&view=rev
Log:
P0145R3 (C++17 evaluation order tweaks): evaluate the right-hand side of
assignment and compound-assignment operators before the left-hand side. (Even
if it's an overloaded operator.)

This completes the implementation of P0145R3 + P0400R0 for all targets except
Windows, where the evaluation order guarantees for <<, >>, and ->* are
unimplementable as the ABI requires the function arguments are evaluated from
right to left (because parameter destructors are run from left to right in the
callee).

Modified:
    cfe/trunk/include/clang/AST/ExprCXX.h
    cfe/trunk/lib/CodeGen/CGCall.cpp
    cfe/trunk/lib/CodeGen/CGExpr.cpp
    cfe/trunk/lib/CodeGen/CGExprCXX.cpp
    cfe/trunk/lib/CodeGen/CodeGenFunction.h
    cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
    cfe/trunk/test/CodeGenCXX/cxx1z-eval-order.cpp
    cfe/trunk/test/CodeGenObjCXX/property-object-reference-2.mm
    cfe/trunk/www/cxx_status.html

Modified: cfe/trunk/include/clang/AST/ExprCXX.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ExprCXX.h?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/ExprCXX.h (original)
+++ cfe/trunk/include/clang/AST/ExprCXX.h Tue Sep 27 18:44:22 2016
@@ -76,6 +76,16 @@ public:
   /// expression refers to.
   OverloadedOperatorKind getOperator() const { return Operator; }
 
+  static bool isAssignmentOp(OverloadedOperatorKind Opc) {
+    return Opc == OO_Equal || Opc == OO_StarEqual ||
+           Opc == OO_SlashEqual || Opc == OO_PercentEqual ||
+           Opc == OO_PlusEqual || Opc == OO_MinusEqual ||
+           Opc == OO_LessLessEqual || Opc == OO_GreaterGreaterEqual ||
+           Opc == OO_AmpEqual || Opc == OO_CaretEqual ||
+           Opc == OO_PipeEqual;
+  }
+  bool isAssignmentOp() const { return isAssignmentOp(getOperator()); }
+
   /// \brief Returns the location of the operator symbol in the expression.
   ///
   /// When \c getOperator()==OO_Call, this is the location of the right

Modified: cfe/trunk/lib/CodeGen/CGCall.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGCall.cpp?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGCall.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGCall.cpp Tue Sep 27 18:44:22 2016
@@ -3172,7 +3172,8 @@ void CodeGenFunction::EmitNonNullArgChec
 void CodeGenFunction::EmitCallArgs(
     CallArgList &Args, ArrayRef<QualType> ArgTypes,
     llvm::iterator_range<CallExpr::const_arg_iterator> ArgRange,
-    const FunctionDecl *CalleeDecl, unsigned ParamsToSkip) {
+    const FunctionDecl *CalleeDecl, unsigned ParamsToSkip,
+    bool ForceRightToLeftEvaluation) {
   assert((int)ArgTypes.size() == (ArgRange.end() - ArgRange.begin()));
 
   auto MaybeEmitImplicitObjectSize = [&](unsigned I, const Expr *Arg) {
@@ -3191,7 +3192,8 @@ void CodeGenFunction::EmitCallArgs(
 
   // We *have* to evaluate arguments from right to left in the MS C++ ABI,
   // because arguments are destroyed left to right in the callee.
-  if (CGM.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) {
+  if (CGM.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee() ||
+      ForceRightToLeftEvaluation) {
     // Insert a stack save if we're going to need any inalloca args.
     bool HasInAllocaArgs = false;
     for (ArrayRef<QualType>::iterator I = ArgTypes.begin(), E = ArgTypes.end();

Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Tue Sep 27 18:44:22 2016
@@ -4121,8 +4121,17 @@ RValue CodeGenFunction::EmitCall(QualTyp
   if (Chain)
     Args.add(RValue::get(Builder.CreateBitCast(Chain, CGM.VoidPtrTy)),
              CGM.getContext().VoidPtrTy);
+
+  // C++17 requires that we evaluate arguments to a call using assignment syntax
+  // right-to-left. It also requires that we evaluate arguments to operators
+  // <<, >>, and ->* left-to-right, but that is not possible under the MS ABI,
+  // so there is no corresponding "force left-to-right" case.
+  bool ForceRightToLeft = false;
+  if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(E))
+    ForceRightToLeft = OCE->isAssignmentOp();
+
   EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), E->arguments(),
-               E->getDirectCallee(), /*ParamsToSkip*/ 0);
+               E->getDirectCallee(), /*ParamsToSkip*/ 0, ForceRightToLeft);
 
   const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeFreeFunctionCall(
       Args, FnType, /*isChainCall=*/Chain);

Modified: cfe/trunk/lib/CodeGen/CGExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprCXX.cpp?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprCXX.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp Tue Sep 27 18:44:22 2016
@@ -28,7 +28,7 @@ static RequiredArgs
 commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, const CXXMethodDecl *MD,
                                   llvm::Value *This, llvm::Value *ImplicitParam,
                                   QualType ImplicitParamTy, const CallExpr *CE,
-                                  CallArgList &Args) {
+                                  CallArgList &Args, CallArgList *RtlArgs) {
   assert(CE == nullptr || isa<CXXMemberCallExpr>(CE) ||
          isa<CXXOperatorCallExpr>(CE));
   assert(MD->isInstance() &&
@@ -61,7 +61,12 @@ commonEmitCXXMemberOrOperatorCall(CodeGe
   RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size(), MD);
 
   // And the rest of the call args.
-  if (CE) {
+  if (RtlArgs) {
+    // Special case: if the caller emitted the arguments right-to-left already
+    // (prior to emitting the *this argument), we're done. This happens for
+    // assignment operators.
+    Args.addFrom(*RtlArgs);
+  } else if (CE) {
     // Special case: skip first argument of CXXOperatorCall (it is "this").
     unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
     CGF.EmitCallArgs(Args, FPT, drop_begin(CE->arguments(), ArgsToSkip),
@@ -77,11 +82,11 @@ commonEmitCXXMemberOrOperatorCall(CodeGe
 RValue CodeGenFunction::EmitCXXMemberOrOperatorCall(
     const CXXMethodDecl *MD, llvm::Value *Callee, ReturnValueSlot ReturnValue,
     llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy,
-    const CallExpr *CE) {
+    const CallExpr *CE, CallArgList *RtlArgs) {
   const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
   CallArgList Args;
   RequiredArgs required = commonEmitCXXMemberOrOperatorCall(
-      *this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args);
+      *this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args, RtlArgs);
   return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required),
                   Callee, ReturnValue, Args, MD);
 }
@@ -92,7 +97,7 @@ RValue CodeGenFunction::EmitCXXDestructo
     StructorType Type) {
   CallArgList Args;
   commonEmitCXXMemberOrOperatorCall(*this, DD, This, ImplicitParam,
-                                    ImplicitParamTy, CE, Args);
+                                    ImplicitParamTy, CE, Args, nullptr);
   return EmitCall(CGM.getTypes().arrangeCXXStructorDeclaration(DD, Type),
                   Callee, ReturnValueSlot(), Args, DD);
 }
@@ -170,6 +175,19 @@ RValue CodeGenFunction::EmitCXXMemberOrO
     }
   }
 
+  // C++17 demands that we evaluate the RHS of a (possibly-compound) assignment
+  // operator before the LHS.
+  CallArgList RtlArgStorage;
+  CallArgList *RtlArgs = nullptr;
+  if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(CE)) {
+    if (OCE->isAssignmentOp()) {
+      RtlArgs = &RtlArgStorage;
+      EmitCallArgs(*RtlArgs, MD->getType()->castAs<FunctionProtoType>(),
+                   drop_begin(CE->arguments(), 1), CE->getDirectCallee(),
+                   /*ParamsToSkip*/0, /*ForceRightToLeftEvaluation*/true);
+    }
+  }
+
   Address This = Address::invalid();
   if (IsArrow)
     This = EmitPointerWithAlignment(Base);
@@ -187,10 +205,12 @@ RValue CodeGenFunction::EmitCXXMemberOrO
       if (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) {
         // We don't like to generate the trivial copy/move assignment operator
         // when it isn't necessary; just produce the proper effect here.
-        // Special case: skip first argument of CXXOperatorCall (it is "this").
-        unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
-        Address RHS = EmitLValue(*(CE->arg_begin() + ArgsToSkip)).getAddress();
-        EmitAggregateAssign(This, RHS, CE->getType());
+        LValue RHS = isa<CXXOperatorCallExpr>(CE)
+                         ? MakeNaturalAlignAddrLValue(
+                               (*RtlArgs)[0].RV.getScalarVal(),
+                               (*(CE->arg_begin() + 1))->getType())
+                         : EmitLValue(*CE->arg_begin());
+        EmitAggregateAssign(This, RHS.getAddress(), CE->getType());
         return RValue::get(This.getPointer());
       }
 
@@ -249,7 +269,8 @@ RValue CodeGenFunction::EmitCXXMemberOrO
         Callee = CGM.GetAddrOfFunction(GlobalDecl(DDtor, Dtor_Complete), Ty);
       }
       EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This.getPointer(),
-                                  /*ImplicitParam=*/nullptr, QualType(), CE);
+                                  /*ImplicitParam=*/nullptr, QualType(), CE,
+                                  nullptr);
     }
     return RValue::get(nullptr);
   }
@@ -282,7 +303,8 @@ RValue CodeGenFunction::EmitCXXMemberOrO
   }
 
   return EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This.getPointer(),
-                                     /*ImplicitParam=*/nullptr, QualType(), CE);
+                                     /*ImplicitParam=*/nullptr, QualType(), CE,
+                                     RtlArgs);
 }
 
 RValue

Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Tue Sep 27 18:44:22 2016
@@ -2867,7 +2867,8 @@ public:
   EmitCXXMemberOrOperatorCall(const CXXMethodDecl *MD, llvm::Value *Callee,
                               ReturnValueSlot ReturnValue, llvm::Value *This,
                               llvm::Value *ImplicitParam,
-                              QualType ImplicitParamTy, const CallExpr *E);
+                              QualType ImplicitParamTy, const CallExpr *E,
+                              CallArgList *RtlArgs);
   RValue EmitCXXDestructorCall(const CXXDestructorDecl *DD, llvm::Value *Callee,
                                llvm::Value *This, llvm::Value *ImplicitParam,
                                QualType ImplicitParamTy, const CallExpr *E,
@@ -3322,7 +3323,8 @@ public:
   void EmitCallArgs(CallArgList &Args, const T *CallArgTypeInfo,
                     llvm::iterator_range<CallExpr::const_arg_iterator> ArgRange,
                     const FunctionDecl *CalleeDecl = nullptr,
-                    unsigned ParamsToSkip = 0) {
+                    unsigned ParamsToSkip = 0,
+                    bool ForceRightToLeftEvaluation = false) {
     SmallVector<QualType, 16> ArgTypes;
     CallExpr::const_arg_iterator Arg = ArgRange.begin();
 
@@ -3362,13 +3364,15 @@ public:
     for (auto *A : llvm::make_range(Arg, ArgRange.end()))
       ArgTypes.push_back(getVarArgType(A));
 
-    EmitCallArgs(Args, ArgTypes, ArgRange, CalleeDecl, ParamsToSkip);
+    EmitCallArgs(Args, ArgTypes, ArgRange, CalleeDecl, ParamsToSkip,
+                 ForceRightToLeftEvaluation);
   }
 
   void EmitCallArgs(CallArgList &Args, ArrayRef<QualType> ArgTypes,
                     llvm::iterator_range<CallExpr::const_arg_iterator> ArgRange,
                     const FunctionDecl *CalleeDecl = nullptr,
-                    unsigned ParamsToSkip = 0);
+                    unsigned ParamsToSkip = 0,
+                    bool ForceRightToLeftEvaluation = false);
 
   /// EmitPointerWithAlignment - Given an expression with a pointer
   /// type, emit the value and compute our best estimate of the

Modified: cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp (original)
+++ cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp Tue Sep 27 18:44:22 2016
@@ -1456,7 +1456,8 @@ void ItaniumCXXABI::EmitDestructorCall(C
     Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
 
   CGF.EmitCXXMemberOrOperatorCall(DD, Callee, ReturnValueSlot(),
-                                  This.getPointer(), VTT, VTTTy, nullptr);
+                                  This.getPointer(), VTT, VTTTy,
+                                  nullptr, nullptr);
 }
 
 void ItaniumCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
@@ -1636,7 +1637,7 @@ llvm::Value *ItaniumCXXABI::EmitVirtualD
 
   CGF.EmitCXXMemberOrOperatorCall(Dtor, Callee, ReturnValueSlot(),
                                   This.getPointer(), /*ImplicitParam=*/nullptr,
-                                  QualType(), CE);
+                                  QualType(), CE, nullptr);
   return nullptr;
 }
 

Modified: cfe/trunk/test/CodeGenCXX/cxx1z-eval-order.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/cxx1z-eval-order.cpp?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/cxx1z-eval-order.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/cxx1z-eval-order.cpp Tue Sep 27 18:44:22 2016
@@ -18,7 +18,8 @@ struct B {
 struct C {
   operator int *();
   A *operator->();
-  void operator->*(B);
+  void operator->*(A);
+  friend void operator->*(C, B);
 
   friend void operator<<(C, B);
   friend void operator>>(C, B);
@@ -137,7 +138,17 @@ int dotstar_lhs_before_rhs() {
   int b = make_a_ptr()->*make_mem_ptr_a();
 
   // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
-  // CHECK: call {{.*}}@{{.*}}make_b{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_a{{.*}}(
+  make_c()->*make_a();
+
+  // FIXME: The corresponding case for Windows ABIs is unimplementable if the
+  // operand has a non-trivially-destructible type, because the order of
+  // construction of function arguments is defined by the ABI there (it's the
+  // reverse of the order in which the parameters are destroyed in the callee).
+  // But we could follow the C++17 rule in the case where the operand type is
+  // trivially-destructible.
+  // CHECK-ITANIUM: call {{.*}}@{{.*}}make_c{{.*}}(
+  // CHECK-ITANIUM: call {{.*}}@{{.*}}make_b{{.*}}(
   make_c()->*make_b();
 
   // CHECK: call {{.*}}@{{.*}}make_a{{.*}}(
@@ -154,61 +165,60 @@ int dotstar_lhs_before_rhs() {
 // CHECK: }
 }
 
-#if 0
-// CHECKDISABLED-LABEL: define {{.*}}@{{.*}}assign_lhs_before_rhs{{.*}}(
+
+// CHECK-LABEL: define {{.*}}@{{.*}}assign_rhs_before_lhs{{.*}}(
 void assign_rhs_before_lhs() {
   extern int &lhs_ref(), rhs();
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}rhs{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}lhs_ref{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}rhs{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}lhs_ref{{.*}}(
   lhs_ref() = rhs();
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}rhs{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}lhs_ref{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}rhs{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}lhs_ref{{.*}}(
   lhs_ref() += rhs();
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}rhs{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}lhs_ref{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}rhs{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}lhs_ref{{.*}}(
   lhs_ref() %= rhs();
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_b{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_b{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
   make_c() = make_b();
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_b{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_b{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
   make_c() += make_b();
-// CHECKDISABLED: }
+// CHECK: }
 }
-#endif
-#if 0
-// CHECKDISABLED-LABEL: define {{.*}}@{{.*}}shift_lhs_before_rhs{{.*}}(
+
+// CHECK-LABEL: define {{.*}}@{{.*}}shift_lhs_before_rhs{{.*}}(
 void shift_lhs_before_rhs() {
   extern int lhs(), rhs();
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}lhs{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}rhs{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}lhs{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}rhs{{.*}}(
   (void)(lhs() << rhs());
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}lhs{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}rhs{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}lhs{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}rhs{{.*}}(
   (void)(lhs() >> rhs());
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_a{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_a{{.*}}(
   make_c() << make_a();
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_a{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_a{{.*}}(
   make_c() >> make_a();
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_b{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
+  // CHECK: call {{.*}}@{{.*}}make_b{{.*}}(
   make_c() << make_b();
 
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
-  // CHECKDISABLED: call {{.*}}@{{.*}}make_b{{.*}}(
+  // FIXME: This is unimplementable for Windows ABIs, see above.
+  // CHECK-ITANIUM: call {{.*}}@{{.*}}make_c{{.*}}(
+  // CHECK-ITANIUM: call {{.*}}@{{.*}}make_b{{.*}}(
   make_c() >> make_b();
-// CHECKDISABLED: }
+// CHECK: }
 }
-#endif

Modified: cfe/trunk/test/CodeGenObjCXX/property-object-reference-2.mm
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjCXX/property-object-reference-2.mm?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenObjCXX/property-object-reference-2.mm (original)
+++ cfe/trunk/test/CodeGenObjCXX/property-object-reference-2.mm Tue Sep 27 18:44:22 2016
@@ -44,8 +44,8 @@ struct TCPPObject
 // CHECK: ret void
 
 // CHECK-LABEL: define internal void @__assign_helper_atomic_property_(%struct.TCPPObject*, %struct.TCPPObject*) #
-// CHECK: [[TWO:%.*]] = load %struct.TCPPObject*, %struct.TCPPObject** [[ADDR:%.*]], align 8
 // CHECK: [[THREE:%.*]] = load %struct.TCPPObject*, %struct.TCPPObject** [[ADDR1:%.*]], align 8
+// CHECK: [[TWO:%.*]] = load %struct.TCPPObject*, %struct.TCPPObject** [[ADDR:%.*]], align 8
 // CHECK: [[CALL:%.*]] = call dereferenceable({{[0-9]+}}) %struct.TCPPObject* @_ZN10TCPPObjectaSERKS_(%struct.TCPPObject* [[TWO]], %struct.TCPPObject* dereferenceable({{[0-9]+}}) [[THREE]])
 // CHECK:  ret void
 

Modified: cfe/trunk/www/cxx_status.html
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/www/cxx_status.html?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/www/cxx_status.html (original)
+++ cfe/trunk/www/cxx_status.html Tue Sep 27 18:44:22 2016
@@ -701,7 +701,7 @@ as the draft C++1z standard evolves.</p>
     <tr>
       <td rowspan=2>Stricter expression evaluation order</td>
       <td><a href="http://wg21.link/p0145r3">P0145R3</a></td>
-      <td class="none" align="center" rowspan=2>No</td>
+      <td class="svn" align="center" rowspan=2>SVN <a href="#p0145">(10)</a></td>
     </tr>
     <tr>
       <td><a href="http://wg21.link/p0400r0">P0400R0</a></td>
@@ -741,6 +741,14 @@ In Clang 3.7, a warning is emitted for a
 </span><br>
 <span id="p0136">(9): This is the resolution to a Defect Report, so is applied
 to all language versions supporting inheriting constructors.
+</span><br>
+<span id="p0145">(10): Under the MS ABI, this feature is not fully implementable,
+because the calling convention requires that function parameters are destroyed
+from left to right in the callee. In order to guarantee that destruction order
+is reverse construction order, the operands of overloaded
+<tt>operator<<</tt>, <tt>operator>></tt>, and <tt>operator->*</tt>
+functions are evaluated right-to-left under the MS ABI when called using operator
+syntax, not left-to-right as P0145R3 requires.
 </span>
 </p>
 




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