MFC r309124:

Upgrade our copies of clang, llvm, lldb, compiler-rt and libc++ to 3.9.0
release, and add lld 3.9.0.  Also completely revamp the build system for
clang, llvm, lldb and their related tools.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm, clang and lld are available here:
<http://llvm.org/releases/3.9.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/clang/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Bryan Drewery, Andrew Turner, Antoine Brodin and Jan
Beich for their help.

Relnotes:	yes

MFC r309147:

Pull in r282174 from upstream llvm trunk (by Krzysztof Parzyszek):

  [PPC] Set SP after loading data from stack frame, if no red zone is
  present

  Follow-up to r280705: Make sure that the SP is only restored after
  all data is loaded from the stack frame, if there is no red zone.

  This completes the fix for
  https://llvm.org/bugs/show_bug.cgi?id=26519.

  Differential Revision: https://reviews.llvm.org/D24466

Reported by:    Mark Millard
PR:             214433

MFC r309149:

Pull in r283060 from upstream llvm trunk (by Hal Finkel):

  [PowerPC] Refactor soft-float support, and enable PPC64 soft float

  This change enables soft-float for PowerPC64, and also makes
  soft-float disable all vector instruction sets for both 32-bit and
  64-bit modes. This latter part is necessary because the PPC backend
  canonicalizes many Altivec vector types to floating-point types, and
  so soft-float breaks scalarization support for many operations. Both
  for embedded targets and for operating-system kernels desiring
  soft-float support, it seems reasonable that disabling hardware
  floating-point also disables vector instructions (embedded targets
  without hardware floating point support are unlikely to have Altivec,
  etc. and operating system kernels desiring not to use floating-point
  registers to lower syscall cost are unlikely to want to use vector
  registers either). If someone needs this to work, we'll need to
  change the fact that we promote many Altivec operations to act on
  v4f32. To make it possible to disable Altivec when soft-float is
  enabled, hardware floating-point support needs to be expressed as a
  positive feature, like the others, and not a negative feature,
  because target features cannot have dependencies on the disabling of
  some other feature. So +soft-float has now become -hard-float.

  Fixes PR26970.

Pull in r283061 from upstream clang trunk (by Hal Finkel):

  [PowerPC] Enable soft-float for PPC64, and +soft-float -> -hard-float

  Enable soft-float support on PPC64, as the backend now supports it.
  Also, the backend now uses -hard-float instead of +soft-float, so set
  the target features accordingly.

  Fixes PR26970.

Reported by:	Mark Millard
PR:		214433

MFC r309212:

Add a few missed clang 3.9.0 files to OptionalObsoleteFiles.

MFC r309262:

Fix packaging for clang, lldb and lld 3.9.0

During the upgrade of clang/llvm etc to 3.9.0 in r309124, the PACKAGE
directive in the usr.bin/clang/*.mk files got dropped accidentally.

Restore it, with a few minor changes and additions:
* Correct license in clang.ucl to NCSA
* Add PACKAGE=clang for clang and most of the "ll" tools
* Put lldb in its own package
* Put lld in its own package

Reviewed by:	gjb, jmallett
Differential Revision: https://reviews.freebsd.org/D8666

MFC r309656:

During the bootstrap phase, when building the minimal llvm library on
PowerPC, add lib/Support/Atomic.cpp.  This is needed because upstream
llvm revision r271821 disabled the use of std::call_once, which causes
some fallback functions from Atomic.cpp to be used instead.

Reported by:	Mark Millard
PR:		214902

MFC r309835:

Tentatively apply https://reviews.llvm.org/D18730 to work around gcc PR
70528 (bogus error: constructor required before non-static data member).
This should fix buildworld with the external gcc package.

Reported by:	https://jenkins.freebsd.org/job/FreeBSD_HEAD_amd64_gcc/

MFC r310194:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
3.9.1 release.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/3.9.1/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/lld/docs/ReleaseNotes.html>

Relnotes:	yes

1 files changed, 236 insertions, 168 deletions

diff --git a/contrib/llvm/tools/clang/lib/Sema/SemaStmt.cpp b/contrib/llvm/tools/clang/lib/Sema/SemaStmt.cpp
index e1b1a47..8e8104e 100644
--- a/contrib/llvm/tools/clang/lib/Sema/SemaStmt.cpp
+++ b/contrib/llvm/tools/clang/lib/Sema/SemaStmt.cpp
@@ -37,6 +37,7 @@
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
+
 using namespace clang;
 using namespace sema;
 
@@ -249,10 +250,10 @@ void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
     // is written in a macro body, only warn if it has the warn_unused_result
     // attribute.
     if (const Decl *FD = CE->getCalleeDecl()) {
-      const FunctionDecl *Func = dyn_cast<FunctionDecl>(FD);
-      if (Func ? Func->hasUnusedResultAttr()
-               : FD->hasAttr<WarnUnusedResultAttr>()) {
-        Diag(Loc, diag::warn_unused_result) << R1 << R2;
+      if (const Attr *A = isa<FunctionDecl>(FD)
+                              ? cast<FunctionDecl>(FD)->getUnusedResultAttr()
+                              : FD->getAttr<WarnUnusedResultAttr>()) {
+        Diag(Loc, diag::warn_unused_result) << A << R1 << R2;
         return;
       }
       if (ShouldSuppress)
@@ -276,8 +277,8 @@ void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
     }
     const ObjCMethodDecl *MD = ME->getMethodDecl();
     if (MD) {
-      if (MD->hasAttr<WarnUnusedResultAttr>()) {
-        Diag(Loc, diag::warn_unused_result) << R1 << R2;
+      if (const auto *A = MD->getAttr<WarnUnusedResultAttr>()) {
+        Diag(Loc, diag::warn_unused_result) << A << R1 << R2;
         return;
       }
     }
@@ -488,36 +489,62 @@ StmtResult Sema::ActOnAttributedStmt(SourceLocation AttrLoc,
   return LS;
 }
 
+namespace {
+class CommaVisitor : public EvaluatedExprVisitor<CommaVisitor> {
+  typedef EvaluatedExprVisitor<CommaVisitor> Inherited;
+  Sema &SemaRef;
+public:
+  CommaVisitor(Sema &SemaRef) : Inherited(SemaRef.Context), SemaRef(SemaRef) {}
+  void VisitBinaryOperator(BinaryOperator *E) {
+    if (E->getOpcode() == BO_Comma)
+      SemaRef.DiagnoseCommaOperator(E->getLHS(), E->getExprLoc());
+    EvaluatedExprVisitor<CommaVisitor>::VisitBinaryOperator(E);
+  }
+};
+}
+
 StmtResult
-Sema::ActOnIfStmt(SourceLocation IfLoc, FullExprArg CondVal, Decl *CondVar,
+Sema::ActOnIfStmt(SourceLocation IfLoc, bool IsConstexpr, Stmt *InitStmt,
+                  ConditionResult Cond,
                   Stmt *thenStmt, SourceLocation ElseLoc,
                   Stmt *elseStmt) {
-  ExprResult CondResult(CondVal.release());
-
-  VarDecl *ConditionVar = nullptr;
-  if (CondVar) {
-    ConditionVar = cast<VarDecl>(CondVar);
-    CondResult = CheckConditionVariable(ConditionVar, IfLoc, true);
-    CondResult = ActOnFinishFullExpr(CondResult.get(), IfLoc);
-  }
-  Expr *ConditionExpr = CondResult.getAs<Expr>();
-  if (ConditionExpr) {
-    DiagnoseUnusedExprResult(thenStmt);
+  if (Cond.isInvalid())
+    Cond = ConditionResult(
+        *this, nullptr,
+        MakeFullExpr(new (Context) OpaqueValueExpr(SourceLocation(),
+                                                   Context.BoolTy, VK_RValue),
+                     IfLoc),
+        false);
+
+  Expr *CondExpr = Cond.get().second;
+  if (!Diags.isIgnored(diag::warn_comma_operator,
+                       CondExpr->getExprLoc()))
+    CommaVisitor(*this).Visit(CondExpr);
+
+  if (!elseStmt)
+    DiagnoseEmptyStmtBody(CondExpr->getLocEnd(), thenStmt,
+                          diag::warn_empty_if_body);
+
+  return BuildIfStmt(IfLoc, IsConstexpr, InitStmt, Cond, thenStmt, ElseLoc,
+                     elseStmt);
+}
+
+StmtResult Sema::BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
+                             Stmt *InitStmt, ConditionResult Cond,
+                             Stmt *thenStmt, SourceLocation ElseLoc,
+                             Stmt *elseStmt) {
+  if (Cond.isInvalid())
+    return StmtError();
 
-    if (!elseStmt) {
-      DiagnoseEmptyStmtBody(ConditionExpr->getLocEnd(), thenStmt,
-                            diag::warn_empty_if_body);
-    }
+  if (IsConstexpr)
+    getCurFunction()->setHasBranchProtectedScope();
 
-    DiagnoseUnusedExprResult(elseStmt);
-  } else {
-    // Create a dummy Expr for the condition for error recovery
-    ConditionExpr = new (Context) OpaqueValueExpr(SourceLocation(),
-                                                  Context.BoolTy, VK_RValue);
-  }
+  DiagnoseUnusedExprResult(thenStmt);
+  DiagnoseUnusedExprResult(elseStmt);
 
-  return new (Context) IfStmt(Context, IfLoc, ConditionVar, ConditionExpr,
-                              thenStmt, ElseLoc, elseStmt);
+  return new (Context)
+      IfStmt(Context, IfLoc, IsConstexpr, InitStmt, Cond.get().first,
+             Cond.get().second, thenStmt, ElseLoc, elseStmt);
 }
 
 namespace {
@@ -579,24 +606,7 @@ static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) {
   return expr->getType();
 }
 
-StmtResult
-Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
-                             Decl *CondVar) {
-  ExprResult CondResult;
-
-  VarDecl *ConditionVar = nullptr;
-  if (CondVar) {
-    ConditionVar = cast<VarDecl>(CondVar);
-    CondResult = CheckConditionVariable(ConditionVar, SourceLocation(), false);
-    if (CondResult.isInvalid())
-      return StmtError();
-
-    Cond = CondResult.get();
-  }
-
-  if (!Cond)
-    return StmtError();
-
+ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
   class SwitchConvertDiagnoser : public ICEConvertDiagnoser {
     Expr *Cond;
 
@@ -644,24 +654,24 @@ Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
     }
   } SwitchDiagnoser(Cond);
 
-  CondResult =
+  ExprResult CondResult =
       PerformContextualImplicitConversion(SwitchLoc, Cond, SwitchDiagnoser);
-  if (CondResult.isInvalid()) return StmtError();
-  Cond = CondResult.get();
+  if (CondResult.isInvalid())
+    return ExprError();
 
   // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
-  CondResult = UsualUnaryConversions(Cond);
-  if (CondResult.isInvalid()) return StmtError();
-  Cond = CondResult.get();
+  return UsualUnaryConversions(CondResult.get());
+}
 
-  CondResult = ActOnFinishFullExpr(Cond, SwitchLoc);
-  if (CondResult.isInvalid())
+StmtResult Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc,
+                                        Stmt *InitStmt, ConditionResult Cond) {
+  if (Cond.isInvalid())
     return StmtError();
-  Cond = CondResult.get();
 
   getCurFunction()->setHasBranchIntoScope();
 
-  SwitchStmt *SS = new (Context) SwitchStmt(Context, ConditionVar, Cond);
+  SwitchStmt *SS = new (Context)
+      SwitchStmt(Context, InitStmt, Cond.get().first, Cond.get().second);
   getCurFunction()->SwitchStack.push_back(SS);
   return SS;
 }
@@ -980,7 +990,8 @@ Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
             << SourceRange(CR->getLHS()->getLocStart(),
                            Hi->getLocEnd());
           CaseRanges.erase(CaseRanges.begin()+i);
-          --i, --e;
+          --i;
+          --e;
           continue;
         }
 
@@ -1221,23 +1232,17 @@ Sema::DiagnoseAssignmentEnum(QualType DstType, QualType SrcType,
     }
 }
 
-StmtResult
-Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond,
-                     Decl *CondVar, Stmt *Body) {
-  ExprResult CondResult(Cond.release());
-
-  VarDecl *ConditionVar = nullptr;
-  if (CondVar) {
-    ConditionVar = cast<VarDecl>(CondVar);
-    CondResult = CheckConditionVariable(ConditionVar, WhileLoc, true);
-    CondResult = ActOnFinishFullExpr(CondResult.get(), WhileLoc);
-    if (CondResult.isInvalid())
-      return StmtError();
-  }
-  Expr *ConditionExpr = CondResult.get();
-  if (!ConditionExpr)
+StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc, ConditionResult Cond,
+                                Stmt *Body) {
+  if (Cond.isInvalid())
     return StmtError();
-  CheckBreakContinueBinding(ConditionExpr);
+
+  auto CondVal = Cond.get();
+  CheckBreakContinueBinding(CondVal.second);
+
+  if (CondVal.second &&
+      !Diags.isIgnored(diag::warn_comma_operator, CondVal.second->getExprLoc()))
+    CommaVisitor(*this).Visit(CondVal.second);
 
   DiagnoseUnusedExprResult(Body);
 
@@ -1245,7 +1250,7 @@ Sema::ActOnWhileStmt(SourceLocation WhileLoc, FullExprArg Cond,
     getCurCompoundScope().setHasEmptyLoopBodies();
 
   return new (Context)
-      WhileStmt(Context, ConditionVar, ConditionExpr, Body, WhileLoc);
+      WhileStmt(Context, CondVal.first, CondVal.second, Body, WhileLoc);
 }
 
 StmtResult
@@ -1255,7 +1260,7 @@ Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
   assert(Cond && "ActOnDoStmt(): missing expression");
 
   CheckBreakContinueBinding(Cond);
-  ExprResult CondResult = CheckBooleanCondition(Cond, DoLoc);
+  ExprResult CondResult = CheckBooleanCondition(DoLoc, Cond);
   if (CondResult.isInvalid())
     return StmtError();
   Cond = CondResult.get();
@@ -1416,6 +1421,18 @@ namespace {
           FoundDecl = true;
     }
 
+    void VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
+      // Only need to visit the semantics for POE.
+      // SyntaticForm doesn't really use the Decal.
+      for (auto *S : POE->semantics()) {
+        if (auto *OVE = dyn_cast<OpaqueValueExpr>(S))
+          // Look past the OVE into the expression it binds.
+          Visit(OVE->getSourceExpr());
+        else
+          Visit(S);
+      }
+    }
+
     bool FoundDeclInUse() { return FoundDecl; }
 
   };  // end class DeclMatcher
@@ -1481,6 +1498,10 @@ namespace {
   // variables Increment and DRE.
   bool ProcessIterationStmt(Sema &S, Stmt* Statement, bool &Increment,
                             DeclRefExpr *&DRE) {
+    if (auto Cleanups = dyn_cast<ExprWithCleanups>(Statement))
+      if (!Cleanups->cleanupsHaveSideEffects())
+        Statement = Cleanups->getSubExpr();
+
     if (UnaryOperator *UO = dyn_cast<UnaryOperator>(Statement)) {
       switch (UO->getOpcode()) {
         default: return false;
@@ -1603,11 +1624,13 @@ void Sema::CheckBreakContinueBinding(Expr *E) {
   }
 }
 
-StmtResult
-Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
-                   Stmt *First, FullExprArg second, Decl *secondVar,
-                   FullExprArg third,
-                   SourceLocation RParenLoc, Stmt *Body) {
+StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
+                              Stmt *First, ConditionResult Second,
+                              FullExprArg third, SourceLocation RParenLoc,
+                              Stmt *Body) {
+  if (Second.isInvalid())
+    return StmtError();
+
   if (!getLangOpts().CPlusPlus) {
     if (DeclStmt *DS = dyn_cast_or_null<DeclStmt>(First)) {
       // C99 6.8.5p3: The declaration part of a 'for' statement shall only
@@ -1625,21 +1648,18 @@ Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
     }
   }
 
-  CheckBreakContinueBinding(second.get());
+  CheckBreakContinueBinding(Second.get().second);
   CheckBreakContinueBinding(third.get());
 
-  CheckForLoopConditionalStatement(*this, second.get(), third.get(), Body);
+  if (!Second.get().first)
+    CheckForLoopConditionalStatement(*this, Second.get().second, third.get(),
+                                     Body);
   CheckForRedundantIteration(*this, third.get(), Body);
 
-  ExprResult SecondResult(second.release());
-  VarDecl *ConditionVar = nullptr;
-  if (secondVar) {
-    ConditionVar = cast<VarDecl>(secondVar);
-    SecondResult = CheckConditionVariable(ConditionVar, ForLoc, true);
-    SecondResult = ActOnFinishFullExpr(SecondResult.get(), ForLoc);
-    if (SecondResult.isInvalid())
-      return StmtError();
-  }
+  if (Second.get().second &&
+      !Diags.isIgnored(diag::warn_comma_operator,
+                       Second.get().second->getExprLoc()))
+    CommaVisitor(*this).Visit(Second.get().second);
 
   Expr *Third  = third.release().getAs<Expr>();
 
@@ -1650,8 +1670,9 @@ Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
   if (isa<NullStmt>(Body))
     getCurCompoundScope().setHasEmptyLoopBodies();
 
-  return new (Context) ForStmt(Context, First, SecondResult.get(), ConditionVar,
-                               Third, Body, ForLoc, LParenLoc, RParenLoc);
+  return new (Context)
+      ForStmt(Context, First, Second.get().second, Second.get().first, Third,
+              Body, ForLoc, LParenLoc, RParenLoc);
 }
 
 /// In an Objective C collection iteration statement:
@@ -1992,8 +2013,9 @@ StmtResult Sema::ActOnCXXForRangeStmt(Scope *S, SourceLocation ForLoc,
   }
 
   return BuildCXXForRangeStmt(ForLoc, CoawaitLoc, ColonLoc, RangeDecl.get(),
-                              /*BeginEndDecl=*/nullptr, /*Cond=*/nullptr,
-                              /*Inc=*/nullptr, DS, RParenLoc, Kind);
+                              /*BeginStmt=*/nullptr, /*EndStmt=*/nullptr,
+                              /*Cond=*/nullptr, /*Inc=*/nullptr,
+                              DS, RParenLoc, Kind);
 }
 
 /// \brief Create the initialization, compare, and increment steps for
@@ -2143,8 +2165,8 @@ struct InvalidateOnErrorScope {
 /// BuildCXXForRangeStmt - Build or instantiate a C++11 for-range statement.
 StmtResult
 Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
-                           SourceLocation ColonLoc,
-                           Stmt *RangeDecl, Stmt *BeginEnd, Expr *Cond,
+                           SourceLocation ColonLoc, Stmt *RangeDecl,
+                           Stmt *Begin, Stmt *End, Expr *Cond,
                            Expr *Inc, Stmt *LoopVarDecl,
                            SourceLocation RParenLoc, BuildForRangeKind Kind) {
   // FIXME: This should not be used during template instantiation. We should
@@ -2170,7 +2192,8 @@ Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
   InvalidateOnErrorScope Invalidate(*this, LoopVar,
                                     LoopVar->getType()->isUndeducedType());
 
-  StmtResult BeginEndDecl = BeginEnd;
+  StmtResult BeginDeclStmt = Begin;
+  StmtResult EndDeclStmt = End;
   ExprResult NotEqExpr = Cond, IncrExpr = Inc;
 
   if (RangeVarType->isDependentType()) {
@@ -2181,7 +2204,7 @@ Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
     // them in properly when we instantiate the loop.
     if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check)
       LoopVar->setType(SubstAutoType(LoopVar->getType(), Context.DependentTy));
-  } else if (!BeginEndDecl.get()) {
+  } else if (!BeginDeclStmt.get()) {
     SourceLocation RangeLoc = RangeVar->getLocation();
 
     const QualType RangeVarNonRefType = RangeVarType.getNonReferenceType();
@@ -2306,20 +2329,21 @@ Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
            "invalid range expression in for loop");
 
     // C++11 [dcl.spec.auto]p7: BeginType and EndType must be the same.
+    // C++1z removes this restriction.
     QualType BeginType = BeginVar->getType(), EndType = EndVar->getType();
     if (!Context.hasSameType(BeginType, EndType)) {
-      Diag(RangeLoc, diag::err_for_range_begin_end_types_differ)
-        << BeginType << EndType;
+      Diag(RangeLoc, getLangOpts().CPlusPlus1z
+                         ? diag::warn_for_range_begin_end_types_differ
+                         : diag::ext_for_range_begin_end_types_differ)
+          << BeginType << EndType;
       NoteForRangeBeginEndFunction(*this, BeginExpr.get(), BEF_begin);
       NoteForRangeBeginEndFunction(*this, EndExpr.get(), BEF_end);
     }
 
-    Decl *BeginEndDecls[] = { BeginVar, EndVar };
-    // Claim the type doesn't contain auto: we've already done the checking.
-    DeclGroupPtrTy BeginEndGroup =
-        BuildDeclaratorGroup(MutableArrayRef<Decl *>(BeginEndDecls, 2),
-                             /*TypeMayContainAuto=*/ false);
-    BeginEndDecl = ActOnDeclStmt(BeginEndGroup, ColonLoc, ColonLoc);
+    BeginDeclStmt =
+        ActOnDeclStmt(ConvertDeclToDeclGroup(BeginVar), ColonLoc, ColonLoc);
+    EndDeclStmt =
+        ActOnDeclStmt(ConvertDeclToDeclGroup(EndVar), ColonLoc, ColonLoc);
 
     const QualType BeginRefNonRefType = BeginType.getNonReferenceType();
     ExprResult BeginRef = BuildDeclRefExpr(BeginVar, BeginRefNonRefType,
@@ -2335,8 +2359,10 @@ Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
     // Build and check __begin != __end expression.
     NotEqExpr = ActOnBinOp(S, ColonLoc, tok::exclaimequal,
                            BeginRef.get(), EndRef.get());
-    NotEqExpr = ActOnBooleanCondition(S, ColonLoc, NotEqExpr.get());
-    NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
+    if (!NotEqExpr.isInvalid())
+      NotEqExpr = CheckBooleanCondition(ColonLoc, NotEqExpr.get());
+    if (!NotEqExpr.isInvalid())
+      NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
     if (NotEqExpr.isInvalid()) {
       Diag(RangeLoc, diag::note_for_range_invalid_iterator)
         << RangeLoc << 0 << BeginRangeRef.get()->getType();
@@ -2394,7 +2420,8 @@ Sema::BuildCXXForRangeStmt(SourceLocation ForLoc, SourceLocation CoawaitLoc,
     return StmtResult();
 
   return new (Context) CXXForRangeStmt(
-      RangeDS, cast_or_null<DeclStmt>(BeginEndDecl.get()), NotEqExpr.get(),
+      RangeDS, cast_or_null<DeclStmt>(BeginDeclStmt.get()),
+      cast_or_null<DeclStmt>(EndDeclStmt.get()), NotEqExpr.get(),
       IncrExpr.get(), LoopVarDS, /*Body=*/nullptr, ForLoc, CoawaitLoc,
       ColonLoc, RParenLoc);
 }
@@ -2426,6 +2453,10 @@ static void DiagnoseForRangeReferenceVariableCopies(Sema &SemaRef,
 
   QualType VariableType = VD->getType();
 
+  if (auto Cleanups = dyn_cast<ExprWithCleanups>(InitExpr))
+    if (!Cleanups->cleanupsHaveSideEffects())
+      InitExpr = Cleanups->getSubExpr();
+
   const MaterializeTemporaryExpr *MTE =
       dyn_cast<MaterializeTemporaryExpr>(InitExpr);
 
@@ -2663,16 +2694,16 @@ Sema::ActOnBreakStmt(SourceLocation BreakLoc, Scope *CurScope) {
 /// \param E The expression being returned from the function or block, or
 /// being thrown.
 ///
-/// \param AllowFunctionParameter Whether we allow function parameters to
-/// be considered NRVO candidates. C++ prohibits this for NRVO itself, but
-/// we re-use this logic to determine whether we should try to move as part of
-/// a return or throw (which does allow function parameters).
+/// \param AllowParamOrMoveConstructible Whether we allow function parameters or
+/// id-expressions that could be moved out of the function to be considered NRVO
+/// candidates. C++ prohibits these for NRVO itself, but we re-use this logic to
+/// determine whether we should try to move as part of a return or throw (which
+/// does allow function parameters).
 ///
 /// \returns The NRVO candidate variable, if the return statement may use the
 /// NRVO, or NULL if there is no such candidate.
-VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType,
-                                       Expr *E,
-                                       bool AllowFunctionParameter) {
+VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType, Expr *E,
+                                       bool AllowParamOrMoveConstructible) {
   if (!getLangOpts().CPlusPlus)
     return nullptr;
 
@@ -2685,13 +2716,13 @@ VarDecl *Sema::getCopyElisionCandidate(QualType ReturnType,
   if (!VD)
     return nullptr;
 
-  if (isCopyElisionCandidate(ReturnType, VD, AllowFunctionParameter))
+  if (isCopyElisionCandidate(ReturnType, VD, AllowParamOrMoveConstructible))
     return VD;
   return nullptr;
 }
 
 bool Sema::isCopyElisionCandidate(QualType ReturnType, const VarDecl *VD,
-                                  bool AllowFunctionParameter) {
+                                  bool AllowParamOrMoveConstructible) {
   QualType VDType = VD->getType();
   // - in a return statement in a function with ...
   // ... a class return type ...
@@ -2699,20 +2730,24 @@ bool Sema::isCopyElisionCandidate(QualType ReturnType, const VarDecl *VD,
     if (!ReturnType->isRecordType())
       return false;
     // ... the same cv-unqualified type as the function return type ...
-    if (!VDType->isDependentType() &&
+    // When considering moving this expression out, allow dissimilar types.
+    if (!AllowParamOrMoveConstructible && !VDType->isDependentType() &&
         !Context.hasSameUnqualifiedType(ReturnType, VDType))
       return false;
   }
 
   // ...object (other than a function or catch-clause parameter)...
   if (VD->getKind() != Decl::Var &&
-      !(AllowFunctionParameter && VD->getKind() == Decl::ParmVar))
+      !(AllowParamOrMoveConstructible && VD->getKind() == Decl::ParmVar))
     return false;
   if (VD->isExceptionVariable()) return false;
 
   // ...automatic...
   if (!VD->hasLocalStorage()) return false;
 
+  if (AllowParamOrMoveConstructible)
+    return true;
+
   // ...non-volatile...
   if (VD->getType().isVolatileQualified()) return false;
 
@@ -2731,7 +2766,7 @@ bool Sema::isCopyElisionCandidate(QualType ReturnType, const VarDecl *VD,
 /// \brief Perform the initialization of a potentially-movable value, which
 /// is the result of return value.
 ///
-/// This routine implements C++0x [class.copy]p33, which attempts to treat
+/// This routine implements C++14 [class.copy]p32, which attempts to treat
 /// returned lvalues as rvalues in certain cases (to prefer move construction),
 /// then falls back to treating them as lvalues if that failed.
 ExprResult
@@ -2740,52 +2775,59 @@ Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
                                       QualType ResultType,
                                       Expr *Value,
                                       bool AllowNRVO) {
-  // C++0x [class.copy]p33:
-  //   When the criteria for elision of a copy operation are met or would
-  //   be met save for the fact that the source object is a function
-  //   parameter, and the object to be copied is designated by an lvalue,
-  //   overload resolution to select the constructor for the copy is first
-  //   performed as if the object were designated by an rvalue.
+  // C++14 [class.copy]p32:
+  // When the criteria for elision of a copy/move operation are met, but not for
+  // an exception-declaration, and the object to be copied is designated by an
+  // lvalue, or when the expression in a return statement is a (possibly
+  // parenthesized) id-expression that names an object with automatic storage
+  // duration declared in the body or parameter-declaration-clause of the
+  // innermost enclosing function or lambda-expression, overload resolution to
+  // select the constructor for the copy is first performed as if the object
+  // were designated by an rvalue.
   ExprResult Res = ExprError();
-  if (AllowNRVO &&
-      (NRVOCandidate || getCopyElisionCandidate(ResultType, Value, true))) {
-    ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack,
-                              Value->getType(), CK_NoOp, Value, VK_XValue);
+
+  if (AllowNRVO && !NRVOCandidate)
+    NRVOCandidate = getCopyElisionCandidate(ResultType, Value, true);
+
+  if (AllowNRVO && NRVOCandidate) {
+    ImplicitCastExpr AsRvalue(ImplicitCastExpr::OnStack, Value->getType(),
+                              CK_NoOp, Value, VK_XValue);
 
     Expr *InitExpr = &AsRvalue;
-    InitializationKind Kind
-      = InitializationKind::CreateCopy(Value->getLocStart(),
-                                       Value->getLocStart());
-    InitializationSequence Seq(*this, Entity, Kind, InitExpr);
 
-    //   [...] If overload resolution fails, or if the type of the first
-    //   parameter of the selected constructor is not an rvalue reference
-    //   to the object's type (possibly cv-qualified), overload resolution
-    //   is performed again, considering the object as an lvalue.
+    InitializationKind Kind = InitializationKind::CreateCopy(
+        Value->getLocStart(), Value->getLocStart());
+
+    InitializationSequence Seq(*this, Entity, Kind, InitExpr);
     if (Seq) {
-      for (InitializationSequence::step_iterator Step = Seq.step_begin(),
-           StepEnd = Seq.step_end();
-           Step != StepEnd; ++Step) {
-        if (Step->Kind != InitializationSequence::SK_ConstructorInitialization)
+      for (const InitializationSequence::Step &Step : Seq.steps()) {
+        if (!(Step.Kind ==
+                  InitializationSequence::SK_ConstructorInitialization ||
+              (Step.Kind == InitializationSequence::SK_UserConversion &&
+               isa<CXXConstructorDecl>(Step.Function.Function))))
           continue;
 
-        CXXConstructorDecl *Constructor
-        = cast<CXXConstructorDecl>(Step->Function.Function);
+        CXXConstructorDecl *Constructor =
+            cast<CXXConstructorDecl>(Step.Function.Function);
 
         const RValueReferenceType *RRefType
           = Constructor->getParamDecl(0)->getType()
                                                  ->getAs<RValueReferenceType>();
 
-        // If we don't meet the criteria, break out now.
+        // [...] If the first overload resolution fails or was not performed, or
+        // if the type of the first parameter of the selected constructor is not
+        // an rvalue reference to the object’s type (possibly cv-qualified),
+        // overload resolution is performed again, considering the object as an
+        // lvalue.
         if (!RRefType ||
             !Context.hasSameUnqualifiedType(RRefType->getPointeeType(),
-                            Context.getTypeDeclType(Constructor->getParent())))
+                                            NRVOCandidate->getType()))
           break;
 
         // Promote "AsRvalue" to the heap, since we now need this
         // expression node to persist.
-        Value = ImplicitCastExpr::Create(Context, Value->getType(),
-                                         CK_NoOp, Value, nullptr, VK_XValue);
+        Value = ImplicitCastExpr::Create(Context, Value->getType(), CK_NoOp,
+                                         Value, nullptr, VK_XValue);
 
         // Complete type-checking the initialization of the return type
         // using the constructor we found.
@@ -2821,8 +2863,21 @@ Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
   CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction());
   QualType FnRetType = CurCap->ReturnType;
   LambdaScopeInfo *CurLambda = dyn_cast<LambdaScopeInfo>(CurCap);
+  bool HasDeducedReturnType =
+      CurLambda && hasDeducedReturnType(CurLambda->CallOperator);
+
+  if (ExprEvalContexts.back().Context == DiscardedStatement &&
+      (HasDeducedReturnType || CurCap->HasImplicitReturnType)) {
+    if (RetValExp) {
+      ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
+      if (ER.isInvalid())
+        return StmtError();
+      RetValExp = ER.get();
+    }
+    return new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
+  }
 
-  if (CurLambda && hasDeducedReturnType(CurLambda->CallOperator)) {
+  if (HasDeducedReturnType) {
     // In C++1y, the return type may involve 'auto'.
     // FIXME: Blocks might have a return type of 'auto' explicitly specified.
     FunctionDecl *FD = CurLambda->CallOperator;
@@ -3066,22 +3121,28 @@ bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
   //  has multiple return statements, the return type is deduced for each return
   //  statement. [...] if the type deduced is not the same in each deduction,
   //  the program is ill-formed.
-  if (AT->isDeduced() && !FD->isInvalidDecl()) {
+  QualType DeducedT = AT->getDeducedType();
+  if (!DeducedT.isNull() && !FD->isInvalidDecl()) {
     AutoType *NewAT = Deduced->getContainedAutoType();
+    // It is possible that NewAT->getDeducedType() is null. When that happens,
+    // we should not crash, instead we ignore this deduction.
+    if (NewAT->getDeducedType().isNull())
+      return false;
+
     CanQualType OldDeducedType = Context.getCanonicalFunctionResultType(
-                                   AT->getDeducedType());
+                                   DeducedT);
     CanQualType NewDeducedType = Context.getCanonicalFunctionResultType(
                                    NewAT->getDeducedType());
     if (!FD->isDependentContext() && OldDeducedType != NewDeducedType) {
       const LambdaScopeInfo *LambdaSI = getCurLambda();
       if (LambdaSI && LambdaSI->HasImplicitReturnType) {
         Diag(ReturnLoc, diag::err_typecheck_missing_return_type_incompatible)
-          << NewAT->getDeducedType() << AT->getDeducedType()
+          << NewAT->getDeducedType() << DeducedT
           << true /*IsLambda*/;
       } else {
         Diag(ReturnLoc, diag::err_auto_fn_different_deductions)
           << (AT->isDecltypeAuto() ? 1 : 0)
-          << NewAT->getDeducedType() << AT->getDeducedType();
+          << NewAT->getDeducedType() << DeducedT;
       }
       return true;
     }
@@ -3097,9 +3158,8 @@ StmtResult
 Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp,
                       Scope *CurScope) {
   StmtResult R = BuildReturnStmt(ReturnLoc, RetValExp);
-  if (R.isInvalid()) {
+  if (R.isInvalid() || ExprEvalContexts.back().Context == DiscardedStatement)
     return R;
-  }
 
   if (VarDecl *VD =
       const_cast<VarDecl*>(cast<ReturnStmt>(R.get())->getNRVOCandidate())) {
@@ -3148,6 +3208,19 @@ StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
   } else // If we don't have a function/method context, bail.
     return StmtError();
 
+  // C++1z: discarded return statements are not considered when deducing a
+  // return type.
+  if (ExprEvalContexts.back().Context == DiscardedStatement &&
+      FnRetType->getContainedAutoType()) {
+    if (RetValExp) {
+      ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
+      if (ER.isInvalid())
+        return StmtError();
+      RetValExp = ER.get();
+    }
+    return new (Context) ReturnStmt(ReturnLoc, RetValExp, nullptr);
+  }
+
   // FIXME: Add a flag to the ScopeInfo to indicate whether we're performing
   // deduction.
   if (getLangOpts().CPlusPlus14) {
@@ -3525,11 +3598,6 @@ template <> struct DenseMapInfo<CatchHandlerType> {
     return LHS == RHS;
   }
 };
-
-// It's OK to treat CatchHandlerType as a POD type.
-template <> struct isPodLike<CatchHandlerType> {
-  static const bool value = true;
-};
 }
 
 namespace {
@@ -3554,7 +3622,7 @@ public:
   bool operator()(const CXXBaseSpecifier *S, CXXBasePath &) {
     if (S->getAccessSpecifier() == AccessSpecifier::AS_public) {
       CatchHandlerType Check(S->getType(), CheckAgainstPointer);
-      auto M = TypesToCheck;
+      const auto &M = TypesToCheck;
       auto I = M.find(Check);
       if (I != M.end()) {
         FoundHandler = I->second;
@@ -3916,9 +3984,9 @@ StmtResult Sema::ActOnCapturedRegionEnd(Stmt *S) {
   CapturedDecl *CD = RSI->TheCapturedDecl;
   RecordDecl *RD = RSI->TheRecordDecl;
 
-  CapturedStmt *Res = CapturedStmt::Create(getASTContext(), S,
-                                           RSI->CapRegionKind, Captures,
-                                           CaptureInits, CD, RD);
+  CapturedStmt *Res = CapturedStmt::Create(
+      getASTContext(), S, static_cast<CapturedRegionKind>(RSI->CapRegionKind),
+      Captures, CaptureInits, CD, RD);
 
   CD->setBody(Res->getCapturedStmt());
   RD->completeDefinition();