vendor/clang/clang-release_80-r354130

26 files changed, 264 insertions, 169 deletions

diff --git a/lib/Basic/Targets/PPC.h b/lib/Basic/Targets/PPC.h
index 058970a0e098..cbe7a9a2fa85 100644
--- a/lib/Basic/Targets/PPC.h
+++ b/lib/Basic/Targets/PPC.h
@@ -331,9 +331,15 @@ public:
       break;
     }
 
-    if (getTriple().isOSFreeBSD()) {
+    switch (getTriple().getOS()) {
+    case llvm::Triple::FreeBSD:
+    case llvm::Triple::NetBSD:
+    case llvm::Triple::OpenBSD:
       LongDoubleWidth = LongDoubleAlign = 64;
       LongDoubleFormat = &llvm::APFloat::IEEEdouble();
+      break;
+    default:
+      break;
     }
 
     // PPC32 supports atomics up to 4 bytes.
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index a718f2f19aa6..ccc657493b28 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -7052,19 +7052,16 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     llvm::Value *Metadata = llvm::MetadataAsValue::get(Context, RegName);
 
     llvm::Type *RegisterType = Int64Ty;
-    llvm::Type *ValueType = Int32Ty;
     llvm::Type *Types[] = { RegisterType };
 
     if (BuiltinID == AArch64::BI_ReadStatusReg) {
       llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::read_register, Types);
-      llvm::Value *Call = Builder.CreateCall(F, Metadata);
 
-      return Builder.CreateTrunc(Call, ValueType);
+      return Builder.CreateCall(F, Metadata);
     }
 
     llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::write_register, Types);
     llvm::Value *ArgValue = EmitScalarExpr(E->getArg(1));
-    ArgValue = Builder.CreateZExt(ArgValue, RegisterType);
 
     return Builder.CreateCall(F, { Metadata, ArgValue });
   }
diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index 5959d889b455..b98657ffd800 100644
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -1631,11 +1631,15 @@ void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
                   ? LangOptions::TrivialAutoVarInitKind::Uninitialized
                   : getContext().getLangOpts().getTrivialAutoVarInit()));
 
-  auto initializeWhatIsTechnicallyUninitialized = [&]() {
+  auto initializeWhatIsTechnicallyUninitialized = [&](Address Loc) {
     if (trivialAutoVarInit ==
         LangOptions::TrivialAutoVarInitKind::Uninitialized)
       return;
 
+    // Only initialize a __block's storage: we always initialize the header.
+    if (emission.IsEscapingByRef)
+      Loc = emitBlockByrefAddress(Loc, &D, /*follow=*/false);
+
     CharUnits Size = getContext().getTypeSizeInChars(type);
     if (!Size.isZero()) {
       switch (trivialAutoVarInit) {
@@ -1713,7 +1717,7 @@ void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
   };
 
   if (isTrivialInitializer(Init)) {
-    initializeWhatIsTechnicallyUninitialized();
+    initializeWhatIsTechnicallyUninitialized(Loc);
     return;
   }
 
@@ -1727,7 +1731,7 @@ void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
   }
 
   if (!constant) {
-    initializeWhatIsTechnicallyUninitialized();
+    initializeWhatIsTechnicallyUninitialized(Loc);
     LValue lv = MakeAddrLValue(Loc, type);
     lv.setNonGC(true);
     return EmitExprAsInit(Init, &D, lv, capturedByInit);
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 244738042cef..2ac59fb4de25 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -3762,13 +3762,15 @@ static bool isVarDeclStrongDefinition(const ASTContext &Context,
     }
   }
 
-  // Microsoft's link.exe doesn't support alignments greater than 32 for common
-  // symbols, so symbols with greater alignment requirements cannot be common.
+  // Microsoft's link.exe doesn't support alignments greater than 32 bytes for
+  // common symbols, so symbols with greater alignment requirements cannot be
+  // common.
   // Other COFF linkers (ld.bfd and LLD) support arbitrary power-of-two
   // alignments for common symbols via the aligncomm directive, so this
   // restriction only applies to MSVC environments.
   if (Context.getTargetInfo().getTriple().isKnownWindowsMSVCEnvironment() &&
-      Context.getTypeAlignIfKnown(D->getType()) > 32)
+      Context.getTypeAlignIfKnown(D->getType()) >
+          Context.toBits(CharUnits::fromQuantity(32)))
     return true;
 
   return false;
diff --git a/lib/CodeGen/TargetInfo.cpp b/lib/CodeGen/TargetInfo.cpp
index f5a770ed9d84..94fccb15ff6e 100644
--- a/lib/CodeGen/TargetInfo.cpp
+++ b/lib/CodeGen/TargetInfo.cpp
@@ -761,6 +761,22 @@ public:
 
   void setTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
                            CodeGen::CodeGenModule &CGM) const override {
+    TargetCodeGenInfo::setTargetAttributes(D, GV, CGM);
+    if (const auto *FD = dyn_cast_or_null<FunctionDecl>(D)) {
+      if (const auto *Attr = FD->getAttr<WebAssemblyImportModuleAttr>()) {
+        llvm::Function *Fn = cast<llvm::Function>(GV);
+        llvm::AttrBuilder B;
+        B.addAttribute("wasm-import-module", Attr->getImportModule());
+        Fn->addAttributes(llvm::AttributeList::FunctionIndex, B);
+      }
+      if (const auto *Attr = FD->getAttr<WebAssemblyImportNameAttr>()) {
+        llvm::Function *Fn = cast<llvm::Function>(GV);
+        llvm::AttrBuilder B;
+        B.addAttribute("wasm-import-name", Attr->getImportName());
+        Fn->addAttributes(llvm::AttributeList::FunctionIndex, B);
+      }
+    }
+
     if (auto *FD = dyn_cast_or_null<FunctionDecl>(D)) {
       llvm::Function *Fn = cast<llvm::Function>(GV);
       if (!FD->doesThisDeclarationHaveABody() && !FD->hasPrototype())
diff --git a/lib/Driver/ToolChains/MSVC.cpp b/lib/Driver/ToolChains/MSVC.cpp
index 7e34b0df5c8c..a164fd68e22e 100644
--- a/lib/Driver/ToolChains/MSVC.cpp
+++ b/lib/Driver/ToolChains/MSVC.cpp
@@ -1408,10 +1408,10 @@ static void TranslateOptArg(Arg *A, llvm::opt::DerivedArgList &DAL,
           DAL.AddFlagArg(
               A, Opts.getOption(options::OPT_fno_omit_frame_pointer));
       } else {
-        // Don't warn about /Oy- in 64-bit builds (where
+        // Don't warn about /Oy- in x86-64 builds (where
         // SupportsForcingFramePointer is false).  The flag having no effect
         // there is a compiler-internal optimization, and people shouldn't have
-        // to special-case their build files for 64-bit clang-cl.
+        // to special-case their build files for x86-64 clang-cl.
         A->claim();
       }
       break;
@@ -1442,8 +1442,8 @@ MSVCToolChain::TranslateArgs(const llvm::opt::DerivedArgList &Args,
   DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());
   const OptTable &Opts = getDriver().getOpts();
 
-  // /Oy and /Oy- only has an effect under X86-32.
-  bool SupportsForcingFramePointer = getArch() == llvm::Triple::x86;
+  // /Oy and /Oy- don't have an effect on X86-64
+  bool SupportsForcingFramePointer = getArch() != llvm::Triple::x86_64;
 
   // The -O[12xd] flag actually expands to several flags.  We must desugar the
   // flags so that options embedded can be negated.  For example, the '-O2' flag
diff --git a/lib/Frontend/InitPreprocessor.cpp b/lib/Frontend/InitPreprocessor.cpp
index 66807b097d40..4cde22ce9aa4 100644
--- a/lib/Frontend/InitPreprocessor.cpp
+++ b/lib/Frontend/InitPreprocessor.cpp
@@ -1059,10 +1059,9 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
 
   // OpenCL definitions.
   if (LangOpts.OpenCL) {
-#define OPENCLEXT(Ext) \
-    if (TI.getSupportedOpenCLOpts().isSupported(#Ext, \
-        LangOpts.OpenCLVersion)) \
-      Builder.defineMacro(#Ext);
+#define OPENCLEXT(Ext)                                                         \
+  if (TI.getSupportedOpenCLOpts().isSupported(#Ext, LangOpts))                 \
+    Builder.defineMacro(#Ext);
 #include "clang/Basic/OpenCLExtensions.def"
 
     auto Arch = TI.getTriple().getArch();
diff --git a/lib/Headers/intrin.h b/lib/Headers/intrin.h
index c86f41faeb88..966258bab4b3 100644
--- a/lib/Headers/intrin.h
+++ b/lib/Headers/intrin.h
@@ -564,8 +564,8 @@ __nop(void) {
 #if defined(__aarch64__)
 unsigned __int64 __getReg(int);
 long _InterlockedAdd(long volatile *Addend, long Value);
-int _ReadStatusReg(int);
-void _WriteStatusReg(int, int);
+__int64 _ReadStatusReg(int);
+void _WriteStatusReg(int, __int64);
 
 static inline unsigned short _byteswap_ushort (unsigned short val) {
   return __builtin_bswap16(val);
diff --git a/lib/Parse/ParseObjc.cpp b/lib/Parse/ParseObjc.cpp
index bd55f7179399..c8d7bda3d6e9 100644
--- a/lib/Parse/ParseObjc.cpp
+++ b/lib/Parse/ParseObjc.cpp
@@ -2741,7 +2741,7 @@ StmtResult Parser::ParseObjCAtStatement(SourceLocation AtLoc) {
 
   // Otherwise, eat the semicolon.
   ExpectAndConsumeSemi(diag::err_expected_semi_after_expr);
-  return Actions.ActOnExprStmt(Res, isExprValueDiscarded());
+  return Actions.ActOnExprStmt(Res);
 }
 
 ExprResult Parser::ParseObjCAtExpression(SourceLocation AtLoc) {
diff --git a/lib/Parse/ParseOpenMP.cpp b/lib/Parse/ParseOpenMP.cpp
index dd2a8aae9f2f..17c3fa3cf2aa 100644
--- a/lib/Parse/ParseOpenMP.cpp
+++ b/lib/Parse/ParseOpenMP.cpp
@@ -314,7 +314,7 @@ Parser::ParseOpenMPDeclareReductionDirective(AccessSpecifier AS) {
     Actions.ActOnOpenMPDeclareReductionCombinerStart(getCurScope(), D);
     ExprResult CombinerResult =
         Actions.ActOnFinishFullExpr(ParseAssignmentExpression().get(),
-                                    D->getLocation(), /*DiscardedValue*/ false);
+                                    D->getLocation(), /*DiscardedValue=*/true);
     Actions.ActOnOpenMPDeclareReductionCombinerEnd(D, CombinerResult.get());
 
     if (CombinerResult.isInvalid() && Tok.isNot(tok::r_paren) &&
@@ -356,7 +356,7 @@ Parser::ParseOpenMPDeclareReductionDirective(AccessSpecifier AS) {
           if (Actions.getLangOpts().CPlusPlus) {
             InitializerResult = Actions.ActOnFinishFullExpr(
                 ParseAssignmentExpression().get(), D->getLocation(),
-                /*DiscardedValue*/ false);
+                /*DiscardedValue=*/true);
           } else {
             ConsumeToken();
             ParseOpenMPReductionInitializerForDecl(OmpPrivParm);
@@ -364,7 +364,7 @@ Parser::ParseOpenMPDeclareReductionDirective(AccessSpecifier AS) {
         } else {
           InitializerResult = Actions.ActOnFinishFullExpr(
               ParseAssignmentExpression().get(), D->getLocation(),
-              /*DiscardedValue*/ false);
+              /*DiscardedValue=*/true);
         }
         Actions.ActOnOpenMPDeclareReductionInitializerEnd(
             D, InitializerResult.get(), OmpPrivParm);
@@ -1455,7 +1455,7 @@ ExprResult Parser::ParseOpenMPParensExpr(StringRef ClauseName,
   ExprResult LHS(ParseCastExpression(
       /*isUnaryExpression=*/false, /*isAddressOfOperand=*/false, NotTypeCast));
   ExprResult Val(ParseRHSOfBinaryExpression(LHS, prec::Conditional));
-  Val = Actions.ActOnFinishFullExpr(Val.get(), ELoc, /*DiscardedValue*/ false);
+  Val = Actions.ActOnFinishFullExpr(Val.get(), ELoc);
 
   // Parse ')'.
   RLoc = Tok.getLocation();
@@ -1711,8 +1711,7 @@ OMPClause *Parser::ParseOpenMPSingleExprWithArgClause(OpenMPClauseKind Kind,
     SourceLocation ELoc = Tok.getLocation();
     ExprResult LHS(ParseCastExpression(false, false, NotTypeCast));
     Val = ParseRHSOfBinaryExpression(LHS, prec::Conditional);
-    Val =
-        Actions.ActOnFinishFullExpr(Val.get(), ELoc, /*DiscardedValue*/ false);
+    Val = Actions.ActOnFinishFullExpr(Val.get(), ELoc);
   }
 
   // Parse ')'.
@@ -1997,8 +1996,7 @@ bool Parser::ParseOpenMPVarList(OpenMPDirectiveKind DKind,
     Data.ColonLoc = Tok.getLocation();
     SourceLocation ELoc = ConsumeToken();
     ExprResult Tail = ParseAssignmentExpression();
-    Tail =
-        Actions.ActOnFinishFullExpr(Tail.get(), ELoc, /*DiscardedValue*/ false);
+    Tail = Actions.ActOnFinishFullExpr(Tail.get(), ELoc);
     if (Tail.isUsable())
       Data.TailExpr = Tail.get();
     else
diff --git a/lib/Parse/ParsePragma.cpp b/lib/Parse/ParsePragma.cpp
index 380eb64997a7..7e9b1011e81a 100644
--- a/lib/Parse/ParsePragma.cpp
+++ b/lib/Parse/ParsePragma.cpp
@@ -693,13 +693,12 @@ void Parser::HandlePragmaOpenCLExtension() {
   if (Name == "all") {
     if (State == Disable) {
       Opt.disableAll();
-      Opt.enableSupportedCore(getLangOpts().OpenCLVersion);
+      Opt.enableSupportedCore(getLangOpts());
     } else {
       PP.Diag(NameLoc, diag::warn_pragma_expected_predicate) << 1;
     }
   } else if (State == Begin) {
-    if (!Opt.isKnown(Name) ||
-        !Opt.isSupported(Name, getLangOpts().OpenCLVersion)) {
+    if (!Opt.isKnown(Name) || !Opt.isSupported(Name, getLangOpts())) {
       Opt.support(Name);
     }
     Actions.setCurrentOpenCLExtension(Name);
@@ -709,9 +708,9 @@ void Parser::HandlePragmaOpenCLExtension() {
     Actions.setCurrentOpenCLExtension("");
   } else if (!Opt.isKnown(Name))
     PP.Diag(NameLoc, diag::warn_pragma_unknown_extension) << Ident;
-  else if (Opt.isSupportedExtension(Name, getLangOpts().OpenCLVersion))
+  else if (Opt.isSupportedExtension(Name, getLangOpts()))
     Opt.enable(Name, State == Enable);
-  else if (Opt.isSupportedCore(Name, getLangOpts().OpenCLVersion))
+  else if (Opt.isSupportedCore(Name, getLangOpts()))
     PP.Diag(NameLoc, diag::warn_pragma_extension_is_core) << Ident;
   else
     PP.Diag(NameLoc, diag::warn_pragma_unsupported_extension) << Ident;
diff --git a/lib/Parse/ParseStmt.cpp b/lib/Parse/ParseStmt.cpp
index 2974e6a245b0..313793c3e8fb 100644
--- a/lib/Parse/ParseStmt.cpp
+++ b/lib/Parse/ParseStmt.cpp
@@ -439,7 +439,7 @@ StmtResult Parser::ParseExprStatement() {
 
   // Otherwise, eat the semicolon.
   ExpectAndConsumeSemi(diag::err_expected_semi_after_expr);
-  return Actions.ActOnExprStmt(Expr, isExprValueDiscarded());
+  return Actions.ActOnExprStmt(Expr);
 }
 
 /// ParseSEHTryBlockCommon
@@ -958,16 +958,6 @@ bool Parser::ConsumeNullStmt(StmtVector &Stmts) {
   return true;
 }
 
-bool Parser::isExprValueDiscarded() {
-  if (Actions.isCurCompoundStmtAStmtExpr()) {
-    // Look to see if the next two tokens close the statement expression;
-    // if so, this expression statement is the last statement in a
-    // statment expression.
-    return Tok.isNot(tok::r_brace) || NextToken().isNot(tok::r_paren);
-  }
-  return true;
-}
-
 /// ParseCompoundStatementBody - Parse a sequence of statements and invoke the
 /// ActOnCompoundStmt action.  This expects the '{' to be the current token, and
 /// consume the '}' at the end of the block.  It does not manipulate the scope
@@ -1072,7 +1062,7 @@ StmtResult Parser::ParseCompoundStatementBody(bool isStmtExpr) {
         // Eat the semicolon at the end of stmt and convert the expr into a
         // statement.
         ExpectAndConsumeSemi(diag::err_expected_semi_after_expr);
-        R = Actions.ActOnExprStmt(Res, isExprValueDiscarded());
+        R = Actions.ActOnExprStmt(Res);
       }
     }
 
@@ -1708,16 +1698,8 @@ StmtResult Parser::ParseForStatement(SourceLocation *TrailingElseLoc) {
     if (!Value.isInvalid()) {
       if (ForEach)
         FirstPart = Actions.ActOnForEachLValueExpr(Value.get());
-      else {
-        // We already know this is not an init-statement within a for loop, so
-        // if we are parsing a C++11 range-based for loop, we should treat this
-        // expression statement as being a discarded value expression because
-        // we will err below. This way we do not warn on an unused expression
-        // that was an error in the first place, like with: for (expr : expr);
-        bool IsRangeBasedFor =
-            getLangOpts().CPlusPlus11 && !ForEach && Tok.is(tok::colon);
-        FirstPart = Actions.ActOnExprStmt(Value, !IsRangeBasedFor);
-      }
+      else
+        FirstPart = Actions.ActOnExprStmt(Value);
     }
 
     if (Tok.is(tok::semi)) {
diff --git a/lib/Parse/ParseStmtAsm.cpp b/lib/Parse/ParseStmtAsm.cpp
index 9b96c5150e56..3f5af7d44f36 100644
--- a/lib/Parse/ParseStmtAsm.cpp
+++ b/lib/Parse/ParseStmtAsm.cpp
@@ -637,7 +637,7 @@ StmtResult Parser::ParseMicrosoftAsmStatement(SourceLocation AsmLoc) {
   // Filter out "fpsw" and "mxcsr". They aren't valid GCC asm clobber
   // constraints. Clang always adds fpsr to the clobber list anyway.
   llvm::erase_if(Clobbers, [](const std::string &C) {
-    return C == "fpsw" || C == "mxcsr";
+    return C == "fpsr" || C == "mxcsr";
   });
 
   // Build the vector of clobber StringRefs.
diff --git a/lib/Sema/Sema.cpp b/lib/Sema/Sema.cpp
index 9fa39968625a..9d33ec519092 100644
--- a/lib/Sema/Sema.cpp
+++ b/lib/Sema/Sema.cpp
@@ -256,11 +256,12 @@ void Sema::Initialize() {
   // Initialize predefined OpenCL types and supported extensions and (optional)
   // core features.
   if (getLangOpts().OpenCL) {
-    getOpenCLOptions().addSupport(Context.getTargetInfo().getSupportedOpenCLOpts());
-    getOpenCLOptions().enableSupportedCore(getLangOpts().OpenCLVersion);
+    getOpenCLOptions().addSupport(
+        Context.getTargetInfo().getSupportedOpenCLOpts());
+    getOpenCLOptions().enableSupportedCore(getLangOpts());
     addImplicitTypedef("sampler_t", Context.OCLSamplerTy);
     addImplicitTypedef("event_t", Context.OCLEventTy);
-    if (getLangOpts().OpenCLVersion >= 200) {
+    if (getLangOpts().OpenCLCPlusPlus || getLangOpts().OpenCLVersion >= 200) {
       addImplicitTypedef("clk_event_t", Context.OCLClkEventTy);
       addImplicitTypedef("queue_t", Context.OCLQueueTy);
       addImplicitTypedef("reserve_id_t", Context.OCLReserveIDTy);
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 8dc1fdb76988..b2c727b5c483 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -10622,16 +10622,16 @@ static void AnalyzeCompoundAssignment(Sema &S, BinaryOperator *E) {
   // The below checks assume source is floating point.
   if (!ResultBT || !RBT || !RBT->isFloatingPoint()) return;
 
-  // If source is floating point but target is not.
-  if (!ResultBT->isFloatingPoint())
-    return DiagnoseFloatingImpCast(S, E, E->getRHS()->getType(),
-                                   E->getExprLoc());
-
-  // If both source and target are floating points.
-  // Builtin FP kinds are ordered by increasing FP rank.
-  if (ResultBT->getKind() < RBT->getKind() &&
-      // We don't want to warn for system macro.
-      !S.SourceMgr.isInSystemMacro(E->getOperatorLoc()))
+  // If source is floating point but target is an integer.
+  if (ResultBT->isInteger())
+    DiagnoseImpCast(S, E, E->getRHS()->getType(), E->getLHS()->getType(),
+                    E->getExprLoc(), diag::warn_impcast_float_integer);
+  // If both source and target are floating points. Builtin FP kinds are ordered
+  // by increasing FP rank. FIXME: except _Float16, we currently emit a bogus
+  // warning.
+  else if (ResultBT->isFloatingPoint() && ResultBT->getKind() < RBT->getKind() &&
+           // We don't want to warn for system macro.
+           !S.SourceMgr.isInSystemMacro(E->getOperatorLoc()))
     // warn about dropping FP rank.
     DiagnoseImpCast(S, E->getRHS(), E->getLHS()->getType(), E->getOperatorLoc(),
                     diag::warn_impcast_float_result_precision);
diff --git a/lib/Sema/SemaCoroutine.cpp b/lib/Sema/SemaCoroutine.cpp
index 181efa6d3dd0..e282bb62f032 100644
--- a/lib/Sema/SemaCoroutine.cpp
+++ b/lib/Sema/SemaCoroutine.cpp
@@ -646,7 +646,7 @@ bool Sema::ActOnCoroutineBodyStart(Scope *SC, SourceLocation KWLoc,
       return StmtError();
     Suspend = BuildResolvedCoawaitExpr(Loc, Suspend.get(),
                                        /*IsImplicit*/ true);
-    Suspend = ActOnFinishFullExpr(Suspend.get(), /*DiscardedValue*/ false);
+    Suspend = ActOnFinishFullExpr(Suspend.get());
     if (Suspend.isInvalid()) {
       Diag(Loc, diag::note_coroutine_promise_suspend_implicitly_required)
           << ((Name == "initial_suspend") ? 0 : 1);
@@ -867,7 +867,7 @@ StmtResult Sema::BuildCoreturnStmt(SourceLocation Loc, Expr *E,
   if (PC.isInvalid())
     return StmtError();
 
-  Expr *PCE = ActOnFinishFullExpr(PC.get(), /*DiscardedValue*/ false).get();
+  Expr *PCE = ActOnFinishFullExpr(PC.get()).get();
 
   Stmt *Res = new (Context) CoreturnStmt(Loc, E, PCE, IsImplicit);
   return Res;
@@ -1236,7 +1236,7 @@ bool CoroutineStmtBuilder::makeNewAndDeleteExpr() {
 
   ExprResult NewExpr =
       S.ActOnCallExpr(S.getCurScope(), NewRef.get(), Loc, NewArgs, Loc);
-  NewExpr = S.ActOnFinishFullExpr(NewExpr.get(), /*DiscardedValue*/ false);
+  NewExpr = S.ActOnFinishFullExpr(NewExpr.get());
   if (NewExpr.isInvalid())
     return false;
 
@@ -1262,8 +1262,7 @@ bool CoroutineStmtBuilder::makeNewAndDeleteExpr() {
 
   ExprResult DeleteExpr =
       S.ActOnCallExpr(S.getCurScope(), DeleteRef.get(), Loc, DeleteArgs, Loc);
-  DeleteExpr =
-      S.ActOnFinishFullExpr(DeleteExpr.get(), /*DiscardedValue*/ false);
+  DeleteExpr = S.ActOnFinishFullExpr(DeleteExpr.get());
   if (DeleteExpr.isInvalid())
     return false;
 
@@ -1348,8 +1347,7 @@ bool CoroutineStmtBuilder::makeOnException() {
 
   ExprResult UnhandledException = buildPromiseCall(S, Fn.CoroutinePromise, Loc,
                                                    "unhandled_exception", None);
-  UnhandledException = S.ActOnFinishFullExpr(UnhandledException.get(), Loc,
-                                             /*DiscardedValue*/ false);
+  UnhandledException = S.ActOnFinishFullExpr(UnhandledException.get(), Loc);
   if (UnhandledException.isInvalid())
     return false;
 
@@ -1402,8 +1400,7 @@ bool CoroutineStmtBuilder::makeGroDeclAndReturnStmt() {
          "get_return_object type must no longer be dependent");
 
   if (FnRetType->isVoidType()) {
-    ExprResult Res =
-        S.ActOnFinishFullExpr(this->ReturnValue, Loc, /*DiscardedValue*/ false);
+    ExprResult Res = S.ActOnFinishFullExpr(this->ReturnValue, Loc);
     if (Res.isInvalid())
       return false;
 
@@ -1435,7 +1432,7 @@ bool CoroutineStmtBuilder::makeGroDeclAndReturnStmt() {
   if (Res.isInvalid())
     return false;
 
-  Res = S.ActOnFinishFullExpr(Res.get(), /*DiscardedValue*/ false);
+  Res = S.ActOnFinishFullExpr(Res.get());
   if (Res.isInvalid())
     return false;
 
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 23c99d45a78d..7ddf2e88b787 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -11200,9 +11200,9 @@ void Sema::AddInitializerToDecl(Decl *RealDecl, Expr *Init, bool DirectInit) {
   //   struct T { S a, b; } t = { Temp(), Temp() }
   //
   // we should destroy the first Temp before constructing the second.
-  ExprResult Result =
-      ActOnFinishFullExpr(Init, VDecl->getLocation(),
-                          /*DiscardedValue*/ false, VDecl->isConstexpr());
+  ExprResult Result = ActOnFinishFullExpr(Init, VDecl->getLocation(),
+                                          false,
+                                          VDecl->isConstexpr());
   if (Result.isInvalid()) {
     VDecl->setInvalidDecl();
     return;
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 139ac8aab433..c4c3598ee7f3 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -5116,11 +5116,22 @@ static void handleObjCBridgeRelatedAttr(Sema &S, Decl *D,
 
 static void handleObjCDesignatedInitializer(Sema &S, Decl *D,
                                             const ParsedAttr &AL) {
+  DeclContext *Ctx = D->getDeclContext();
+
+  // This attribute can only be applied to methods in interfaces or class
+  // extensions.
+  if (!isa<ObjCInterfaceDecl>(Ctx) &&
+      !(isa<ObjCCategoryDecl>(Ctx) &&
+        cast<ObjCCategoryDecl>(Ctx)->IsClassExtension())) {
+    S.Diag(D->getLocation(), diag::err_designated_init_attr_non_init);
+    return;
+  }
+
   ObjCInterfaceDecl *IFace;
-  if (auto *CatDecl = dyn_cast<ObjCCategoryDecl>(D->getDeclContext()))
+  if (auto *CatDecl = dyn_cast<ObjCCategoryDecl>(Ctx))
     IFace = CatDecl->getClassInterface();
   else
-    IFace = cast<ObjCInterfaceDecl>(D->getDeclContext());
+    IFace = cast<ObjCInterfaceDecl>(Ctx);
 
   if (!IFace)
     return;
@@ -5577,6 +5588,51 @@ static void handleAVRSignalAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   handleSimpleAttribute<AVRSignalAttr>(S, D, AL);
 }
 
+static void handleWebAssemblyImportModuleAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+  if (!isFunctionOrMethod(D)) {
+    S.Diag(D->getLocation(), diag::warn_attribute_wrong_decl_type)
+        << "'import_module'" << ExpectedFunction;
+    return;
+  }
+
+  auto *FD = cast<FunctionDecl>(D);
+  if (FD->isThisDeclarationADefinition()) {
+    S.Diag(D->getLocation(), diag::err_alias_is_definition) << FD << 0;
+    return;
+  }
+
+  StringRef Str;
+  SourceLocation ArgLoc;
+  if (!S.checkStringLiteralArgumentAttr(AL, 0, Str, &ArgLoc))
+    return;
+
+  FD->addAttr(::new (S.Context) WebAssemblyImportModuleAttr(
+      AL.getRange(), S.Context, Str,
+      AL.getAttributeSpellingListIndex()));
+}
+
+static void handleWebAssemblyImportNameAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+  if (!isFunctionOrMethod(D)) {
+    S.Diag(D->getLocation(), diag::warn_attribute_wrong_decl_type)
+        << "'import_name'" << ExpectedFunction;
+    return;
+  }
+
+  auto *FD = cast<FunctionDecl>(D);
+  if (FD->isThisDeclarationADefinition()) {
+    S.Diag(D->getLocation(), diag::err_alias_is_definition) << FD << 0;
+    return;
+  }
+
+  StringRef Str;
+  SourceLocation ArgLoc;
+  if (!S.checkStringLiteralArgumentAttr(AL, 0, Str, &ArgLoc))
+    return;
+
+  FD->addAttr(::new (S.Context) WebAssemblyImportNameAttr(
+      AL.getRange(), S.Context, Str,
+      AL.getAttributeSpellingListIndex()));
+}
 
 static void handleRISCVInterruptAttr(Sema &S, Decl *D,
                                      const ParsedAttr &AL) {
@@ -6330,6 +6386,12 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
   case ParsedAttr::AT_AVRSignal:
     handleAVRSignalAttr(S, D, AL);
     break;
+  case ParsedAttr::AT_WebAssemblyImportModule:
+    handleWebAssemblyImportModuleAttr(S, D, AL);
+    break;
+  case ParsedAttr::AT_WebAssemblyImportName:
+    handleWebAssemblyImportNameAttr(S, D, AL);
+    break;
   case ParsedAttr::AT_IBAction:
     handleSimpleAttribute<IBActionAttr>(S, D, AL);
     break;
@@ -7016,6 +7078,17 @@ void Sema::ProcessDeclAttributeList(Scope *S, Decl *D,
       }
     }
   }
+
+  // Do this check after processing D's attributes because the attribute
+  // objc_method_family can change whether the given method is in the init
+  // family, and it can be applied after objc_designated_initializer. This is a
+  // bit of a hack, but we need it to be compatible with versions of clang that
+  // processed the attribute list in the wrong order.
+  if (D->hasAttr<ObjCDesignatedInitializerAttr>() &&
+      cast<ObjCMethodDecl>(D)->getMethodFamily() != OMF_init) {
+    Diag(D->getLocation(), diag::err_designated_init_attr_non_init);
+    D->dropAttr<ObjCDesignatedInitializerAttr>();
+  }
 }
 
 // Helper for delayed processing TransparentUnion attribute.
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 8b3556f715bf..950a63aa451b 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -1205,7 +1205,7 @@ static bool checkTupleLikeDecomposition(Sema &S,
     E = Seq.Perform(S, Entity, Kind, Init);
     if (E.isInvalid())
       return true;
-    E = S.ActOnFinishFullExpr(E.get(), Loc, /*DiscardedValue*/ false);
+    E = S.ActOnFinishFullExpr(E.get(), Loc);
     if (E.isInvalid())
       return true;
     RefVD->setInit(E.get());
@@ -3686,7 +3686,7 @@ void Sema::ActOnFinishCXXInClassMemberInitializer(Decl *D,
   // C++11 [class.base.init]p7:
   //   The initialization of each base and member constitutes a
   //   full-expression.
-  Init = ActOnFinishFullExpr(Init.get(), InitLoc, /*DiscardedValue*/ false);
+  Init = ActOnFinishFullExpr(Init.get(), InitLoc);
   if (Init.isInvalid()) {
     FD->setInvalidDecl();
     return;
@@ -4044,8 +4044,7 @@ Sema::BuildMemberInitializer(ValueDecl *Member, Expr *Init,
     // C++11 [class.base.init]p7:
     //   The initialization of each base and member constitutes a
     //   full-expression.
-    MemberInit = ActOnFinishFullExpr(MemberInit.get(), InitRange.getBegin(),
-                                     /*DiscardedValue*/ false);
+    MemberInit = ActOnFinishFullExpr(MemberInit.get(), InitRange.getBegin());
     if (MemberInit.isInvalid())
       return true;
 
@@ -4100,8 +4099,8 @@ Sema::BuildDelegatingInitializer(TypeSourceInfo *TInfo, Expr *Init,
   // C++11 [class.base.init]p7:
   //   The initialization of each base and member constitutes a
   //   full-expression.
-  DelegationInit = ActOnFinishFullExpr(
-      DelegationInit.get(), InitRange.getBegin(), /*DiscardedValue*/ false);
+  DelegationInit = ActOnFinishFullExpr(DelegationInit.get(),
+                                       InitRange.getBegin());
   if (DelegationInit.isInvalid())
     return true;
 
@@ -4230,8 +4229,7 @@ Sema::BuildBaseInitializer(QualType BaseType, TypeSourceInfo *BaseTInfo,
   // C++11 [class.base.init]p7:
   //   The initialization of each base and member constitutes a
   //   full-expression.
-  BaseInit = ActOnFinishFullExpr(BaseInit.get(), InitRange.getBegin(),
-                                 /*DiscardedValue*/ false);
+  BaseInit = ActOnFinishFullExpr(BaseInit.get(), InitRange.getBegin());
   if (BaseInit.isInvalid())
     return true;
 
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 2bcd47abe356..db0c62630a9e 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -4723,9 +4723,8 @@ bool Sema::CheckCXXDefaultArgExpr(SourceLocation CallLoc, FunctionDecl *FD,
     if (Result.isInvalid())
       return true;
 
-    Result =
-        ActOnFinishFullExpr(Result.getAs<Expr>(), Param->getOuterLocStart(),
-                            /*DiscardedValue*/ false);
+    Result = ActOnFinishFullExpr(Result.getAs<Expr>(),
+                                 Param->getOuterLocStart());
     if (Result.isInvalid())
       return true;
 
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 8c89a3cee3db..cce7a216548f 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -7815,8 +7815,6 @@ ExprResult Sema::ActOnFinishFullExpr(Expr *FE, SourceLocation CC,
     FullExpr = IgnoredValueConversions(FullExpr.get());
     if (FullExpr.isInvalid())
       return ExprError();
-
-    DiagnoseUnusedExprResult(FullExpr.get());
   }
 
   FullExpr = CorrectDelayedTyposInExpr(FullExpr.get());
diff --git a/lib/Sema/SemaLambda.cpp b/lib/Sema/SemaLambda.cpp
index af233b96d69b..4e002a853dc2 100644
--- a/lib/Sema/SemaLambda.cpp
+++ b/lib/Sema/SemaLambda.cpp
@@ -1724,7 +1724,7 @@ ExprResult Sema::BuildBlockForLambdaConversion(SourceLocation CurrentLocation,
                                                  /*NRVO=*/false),
       CurrentLocation, Src);
   if (!Init.isInvalid())
-    Init = ActOnFinishFullExpr(Init.get(), /*DiscardedValue*/ false);
+    Init = ActOnFinishFullExpr(Init.get());
 
   if (Init.isInvalid())
     return ExprError();
diff --git a/lib/Sema/SemaOpenMP.cpp b/lib/Sema/SemaOpenMP.cpp
index 36048a38b999..aedec746af9e 100644
--- a/lib/Sema/SemaOpenMP.cpp
+++ b/lib/Sema/SemaOpenMP.cpp
@@ -5367,7 +5367,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
         LastIteration.get(), UB.get());
     EUB = SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, UB.get(),
                              CondOp.get());
-    EUB = SemaRef.ActOnFinishFullExpr(EUB.get(), /*DiscardedValue*/ false);
+    EUB = SemaRef.ActOnFinishFullExpr(EUB.get());
 
     // If we have a combined directive that combines 'distribute', 'for' or
     // 'simd' we need to be able to access the bounds of the schedule of the
@@ -5396,8 +5396,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
                                      LastIteration.get(), CombUB.get());
       CombEUB = SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, CombUB.get(),
                                    CombCondOp.get());
-      CombEUB =
-          SemaRef.ActOnFinishFullExpr(CombEUB.get(), /*DiscardedValue*/ false);
+      CombEUB = SemaRef.ActOnFinishFullExpr(CombEUB.get());
 
       const CapturedDecl *CD = cast<CapturedStmt>(AStmt)->getCapturedDecl();
       // We expect to have at least 2 more parameters than the 'parallel'
@@ -5431,7 +5430,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
             ? LB.get()
             : SemaRef.ActOnIntegerConstant(SourceLocation(), 0).get();
     Init = SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, IV.get(), RHS);
-    Init = SemaRef.ActOnFinishFullExpr(Init.get(), /*DiscardedValue*/ false);
+    Init = SemaRef.ActOnFinishFullExpr(Init.get());
 
     if (isOpenMPLoopBoundSharingDirective(DKind)) {
       Expr *CombRHS =
@@ -5442,8 +5441,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
               : SemaRef.ActOnIntegerConstant(SourceLocation(), 0).get();
       CombInit =
           SemaRef.BuildBinOp(CurScope, InitLoc, BO_Assign, IV.get(), CombRHS);
-      CombInit =
-          SemaRef.ActOnFinishFullExpr(CombInit.get(), /*DiscardedValue*/ false);
+      CombInit = SemaRef.ActOnFinishFullExpr(CombInit.get());
     }
   }
 
@@ -5475,7 +5473,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
   if (!Inc.isUsable())
     return 0;
   Inc = SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, IV.get(), Inc.get());
-  Inc = SemaRef.ActOnFinishFullExpr(Inc.get(), /*DiscardedValue*/ false);
+  Inc = SemaRef.ActOnFinishFullExpr(Inc.get());
   if (!Inc.isUsable())
     return 0;
 
@@ -5493,8 +5491,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
     // LB = LB + ST
     NextLB =
         SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, LB.get(), NextLB.get());
-    NextLB =
-        SemaRef.ActOnFinishFullExpr(NextLB.get(), /*DiscardedValue*/ false);
+    NextLB = SemaRef.ActOnFinishFullExpr(NextLB.get());
     if (!NextLB.isUsable())
       return 0;
     // UB + ST
@@ -5504,8 +5501,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
     // UB = UB + ST
     NextUB =
         SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, UB.get(), NextUB.get());
-    NextUB =
-        SemaRef.ActOnFinishFullExpr(NextUB.get(), /*DiscardedValue*/ false);
+    NextUB = SemaRef.ActOnFinishFullExpr(NextUB.get());
     if (!NextUB.isUsable())
       return 0;
     if (isOpenMPLoopBoundSharingDirective(DKind)) {
@@ -5516,8 +5512,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
       // LB = LB + ST
       CombNextLB = SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, CombLB.get(),
                                       CombNextLB.get());
-      CombNextLB = SemaRef.ActOnFinishFullExpr(CombNextLB.get(),
-                                               /*DiscardedValue*/ false);
+      CombNextLB = SemaRef.ActOnFinishFullExpr(CombNextLB.get());
       if (!CombNextLB.isUsable())
         return 0;
       // UB + ST
@@ -5528,8 +5523,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
       // UB = UB + ST
       CombNextUB = SemaRef.BuildBinOp(CurScope, IncLoc, BO_Assign, CombUB.get(),
                                       CombNextUB.get());
-      CombNextUB = SemaRef.ActOnFinishFullExpr(CombNextUB.get(),
-                                               /*DiscardedValue*/ false);
+      CombNextUB = SemaRef.ActOnFinishFullExpr(CombNextUB.get());
       if (!CombNextUB.isUsable())
         return 0;
     }
@@ -5550,8 +5544,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
     assert(DistInc.isUsable() && "distribute inc expr was not built");
     DistInc = SemaRef.BuildBinOp(CurScope, DistIncLoc, BO_Assign, IV.get(),
                                  DistInc.get());
-    DistInc =
-        SemaRef.ActOnFinishFullExpr(DistInc.get(), /*DiscardedValue*/ false);
+    DistInc = SemaRef.ActOnFinishFullExpr(DistInc.get());
     assert(DistInc.isUsable() && "distribute inc expr was not built");
 
     // Build expression: UB = min(UB, prevUB) for #for in composite or combined
@@ -5563,8 +5556,7 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
         DistEUBLoc, DistEUBLoc, IsUBGreater.get(), PrevUB.get(), UB.get());
     PrevEUB = SemaRef.BuildBinOp(CurScope, DistIncLoc, BO_Assign, UB.get(),
                                  CondOp.get());
-    PrevEUB =
-        SemaRef.ActOnFinishFullExpr(PrevEUB.get(), /*DiscardedValue*/ false);
+    PrevEUB = SemaRef.ActOnFinishFullExpr(PrevEUB.get());
 
     // Build IV <= PrevUB to be used in parallel for is in combination with
     // a distribute directive with schedule(static, 1)
@@ -5680,10 +5672,8 @@ checkOpenMPLoop(OpenMPDirectiveKind DKind, Expr *CollapseLoopCountExpr,
   Built.IterationVarRef = IV.get();
   Built.LastIteration = LastIteration.get();
   Built.NumIterations = NumIterations.get();
-  Built.CalcLastIteration = SemaRef
-                                .ActOnFinishFullExpr(CalcLastIteration.get(),
-                                                     /*DiscardedValue*/ false)
-                                .get();
+  Built.CalcLastIteration =
+      SemaRef.ActOnFinishFullExpr(CalcLastIteration.get()).get();
   Built.PreCond = PreCond.get();
   Built.PreInits = buildPreInits(C, Captures);
   Built.Cond = Cond.get();
@@ -10358,8 +10348,8 @@ OMPClause *Sema::ActOnOpenMPLastprivateClause(ArrayRef<Expr *> VarList,
                                          PseudoDstExpr, PseudoSrcExpr);
     if (AssignmentOp.isInvalid())
       continue;
-    AssignmentOp =
-        ActOnFinishFullExpr(AssignmentOp.get(), ELoc, /*DiscardedValue*/ false);
+    AssignmentOp = ActOnFinishFullExpr(AssignmentOp.get(), ELoc,
+                                       /*DiscardedValue=*/true);
     if (AssignmentOp.isInvalid())
       continue;
 
@@ -11357,8 +11347,7 @@ static bool actOnOMPReductionKindClause(
                            BO_Assign, LHSDRE, ConditionalOp);
         }
         if (ReductionOp.isUsable())
-          ReductionOp = S.ActOnFinishFullExpr(ReductionOp.get(),
-                                              /*DiscardedValue*/ false);
+          ReductionOp = S.ActOnFinishFullExpr(ReductionOp.get());
       }
       if (!ReductionOp.isUsable())
         continue;
@@ -11688,7 +11677,7 @@ OMPClause *Sema::ActOnOpenMPLinearClause(
         buildDeclRefExpr(*this, SaveVar, StepExpr->getType(), StepLoc);
     ExprResult CalcStep =
         BuildBinOp(CurScope, StepLoc, BO_Assign, SaveRef.get(), StepExpr);
-    CalcStep = ActOnFinishFullExpr(CalcStep.get(), /*DiscardedValue*/ false);
+    CalcStep = ActOnFinishFullExpr(CalcStep.get());
 
     // Warn about zero linear step (it would be probably better specified as
     // making corresponding variables 'const').
@@ -11776,7 +11765,7 @@ static bool FinishOpenMPLinearClause(OMPLinearClause &Clause, DeclRefExpr *IV,
     else
       Update = *CurPrivate;
     Update = SemaRef.ActOnFinishFullExpr(Update.get(), DE->getBeginLoc(),
-                                         /*DiscardedValue*/ false);
+                                         /*DiscardedValue=*/true);
 
     // Build final: Var = InitExpr + NumIterations * Step
     ExprResult Final;
@@ -11787,7 +11776,7 @@ static bool FinishOpenMPLinearClause(OMPLinearClause &Clause, DeclRefExpr *IV,
     else
       Final = *CurPrivate;
     Final = SemaRef.ActOnFinishFullExpr(Final.get(), DE->getBeginLoc(),
-                                        /*DiscardedValue*/ false);
+                                        /*DiscardedValue=*/true);
 
     if (!Update.isUsable() || !Final.isUsable()) {
       Updates.push_back(nullptr);
@@ -11955,7 +11944,7 @@ OMPClause *Sema::ActOnOpenMPCopyinClause(ArrayRef<Expr *> VarList,
     if (AssignmentOp.isInvalid())
       continue;
     AssignmentOp = ActOnFinishFullExpr(AssignmentOp.get(), DE->getExprLoc(),
-                                       /*DiscardedValue*/ false);
+                                       /*DiscardedValue=*/true);
     if (AssignmentOp.isInvalid())
       continue;
 
@@ -12063,8 +12052,8 @@ OMPClause *Sema::ActOnOpenMPCopyprivateClause(ArrayRef<Expr *> VarList,
         DSAStack->getCurScope(), ELoc, BO_Assign, PseudoDstExpr, PseudoSrcExpr);
     if (AssignmentOp.isInvalid())
       continue;
-    AssignmentOp =
-        ActOnFinishFullExpr(AssignmentOp.get(), ELoc, /*DiscardedValue*/ false);
+    AssignmentOp = ActOnFinishFullExpr(AssignmentOp.get(), ELoc,
+                                       /*DiscardedValue=*/true);
     if (AssignmentOp.isInvalid())
       continue;
 
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index 9e30c9a396c0..dacf8d0cf4e7 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -42,11 +42,12 @@
 using namespace clang;
 using namespace sema;
 
-StmtResult Sema::ActOnExprStmt(ExprResult FE, bool DiscardedValue) {
+StmtResult Sema::ActOnExprStmt(ExprResult FE) {
   if (FE.isInvalid())
     return StmtError();
 
-  FE = ActOnFinishFullExpr(FE.get(), FE.get()->getExprLoc(), DiscardedValue);
+  FE = ActOnFinishFullExpr(FE.get(), FE.get()->getExprLoc(),
+                           /*DiscardedValue*/ true);
   if (FE.isInvalid())
     return StmtError();
 
@@ -347,10 +348,6 @@ sema::CompoundScopeInfo &Sema::getCurCompoundScope() const {
   return getCurFunction()->CompoundScopes.back();
 }
 
-bool Sema::isCurCompoundStmtAStmtExpr() const {
-  return getCurCompoundScope().IsStmtExpr;
-}
-
 StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
                                    ArrayRef<Stmt *> Elts, bool isStmtExpr) {
   const unsigned NumElts = Elts.size();
@@ -373,6 +370,14 @@ StmtResult Sema::ActOnCompoundStmt(SourceLocation L, SourceLocation R,
       Diag(D->getLocation(), diag::ext_mixed_decls_code);
     }
   }
+  // Warn about unused expressions in statements.
+  for (unsigned i = 0; i != NumElts; ++i) {
+    // Ignore statements that are last in a statement expression.
+    if (isStmtExpr && i == NumElts - 1)
+      continue;
+
+    DiagnoseUnusedExprResult(Elts[i]);
+  }
 
   // Check for suspicious empty body (null statement) in `for' and `while'
   // statements.  Don't do anything for template instantiations, this just adds
@@ -464,12 +469,15 @@ Sema::ActOnCaseStmt(SourceLocation CaseLoc, ExprResult LHSVal,
 
 /// ActOnCaseStmtBody - This installs a statement as the body of a case.
 void Sema::ActOnCaseStmtBody(Stmt *S, Stmt *SubStmt) {
+  DiagnoseUnusedExprResult(SubStmt);
   cast<CaseStmt>(S)->setSubStmt(SubStmt);
 }
 
 StmtResult
 Sema::ActOnDefaultStmt(SourceLocation DefaultLoc, SourceLocation ColonLoc,
                        Stmt *SubStmt, Scope *CurScope) {
+  DiagnoseUnusedExprResult(SubStmt);
+
   if (getCurFunction()->SwitchStack.empty()) {
     Diag(DefaultLoc, diag::err_default_not_in_switch);
     return SubStmt;
@@ -563,6 +571,9 @@ StmtResult Sema::BuildIfStmt(SourceLocation IfLoc, bool IsConstexpr,
   if (IsConstexpr || isa<ObjCAvailabilityCheckExpr>(Cond.get().second))
     setFunctionHasBranchProtectedScope();
 
+  DiagnoseUnusedExprResult(thenStmt);
+  DiagnoseUnusedExprResult(elseStmt);
+
   return IfStmt::Create(Context, IfLoc, IsConstexpr, InitStmt, Cond.get().first,
                         Cond.get().second, thenStmt, ElseLoc, elseStmt);
 }
@@ -1290,6 +1301,8 @@ StmtResult Sema::ActOnWhileStmt(SourceLocation WhileLoc, ConditionResult Cond,
       !Diags.isIgnored(diag::warn_comma_operator, CondVal.second->getExprLoc()))
     CommaVisitor(*this).Visit(CondVal.second);
 
+  DiagnoseUnusedExprResult(Body);
+
   if (isa<NullStmt>(Body))
     getCurCompoundScope().setHasEmptyLoopBodies();
 
@@ -1309,7 +1322,7 @@ Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
     return StmtError();
   Cond = CondResult.get();
 
-  CondResult = ActOnFinishFullExpr(Cond, DoLoc, /*DiscardedValue*/ false);
+  CondResult = ActOnFinishFullExpr(Cond, DoLoc);
   if (CondResult.isInvalid())
     return StmtError();
   Cond = CondResult.get();
@@ -1319,6 +1332,8 @@ Sema::ActOnDoStmt(SourceLocation DoLoc, Stmt *Body,
       !Diags.isIgnored(diag::warn_comma_operator, Cond->getExprLoc()))
     CommaVisitor(*this).Visit(Cond);
 
+  DiagnoseUnusedExprResult(Body);
+
   return new (Context) DoStmt(Body, Cond, DoLoc, WhileLoc, CondRParen);
 }
 
@@ -1763,6 +1778,11 @@ StmtResult Sema::ActOnForStmt(SourceLocation ForLoc, SourceLocation LParenLoc,
     CommaVisitor(*this).Visit(Second.get().second);
 
   Expr *Third  = third.release().getAs<Expr>();
+
+  DiagnoseUnusedExprResult(First);
+  DiagnoseUnusedExprResult(Third);
+  DiagnoseUnusedExprResult(Body);
+
   if (isa<NullStmt>(Body))
     getCurCompoundScope().setHasEmptyLoopBodies();
 
@@ -1782,7 +1802,7 @@ StmtResult Sema::ActOnForEachLValueExpr(Expr *E) {
   if (result.isInvalid()) return StmtError();
   E = result.get();
 
-  ExprResult FullExpr = ActOnFinishFullExpr(E, /*DiscardedValue*/ false);
+  ExprResult FullExpr = ActOnFinishFullExpr(E);
   if (FullExpr.isInvalid())
     return StmtError();
   return StmtResult(static_cast<Stmt*>(FullExpr.get()));
@@ -1936,8 +1956,7 @@ Sema::ActOnObjCForCollectionStmt(SourceLocation ForLoc,
   if (CollectionExprResult.isInvalid())
     return StmtError();
 
-  CollectionExprResult =
-      ActOnFinishFullExpr(CollectionExprResult.get(), /*DiscardedValue*/ false);
+  CollectionExprResult = ActOnFinishFullExpr(CollectionExprResult.get());
   if (CollectionExprResult.isInvalid())
     return StmtError();
 
@@ -2574,8 +2593,7 @@ StmtResult Sema::BuildCXXForRangeStmt(SourceLocation ForLoc,
     if (!NotEqExpr.isInvalid())
       NotEqExpr = CheckBooleanCondition(ColonLoc, NotEqExpr.get());
     if (!NotEqExpr.isInvalid())
-      NotEqExpr =
-          ActOnFinishFullExpr(NotEqExpr.get(), /*DiscardedValue*/ false);
+      NotEqExpr = ActOnFinishFullExpr(NotEqExpr.get());
     if (NotEqExpr.isInvalid()) {
       Diag(RangeLoc, diag::note_for_range_invalid_iterator)
         << RangeLoc << 0 << BeginRangeRef.get()->getType();
@@ -2598,7 +2616,7 @@ StmtResult Sema::BuildCXXForRangeStmt(SourceLocation ForLoc,
       // co_await during the initial parse.
       IncrExpr = ActOnCoawaitExpr(S, CoawaitLoc, IncrExpr.get());
     if (!IncrExpr.isInvalid())
-      IncrExpr = ActOnFinishFullExpr(IncrExpr.get(), /*DiscardedValue*/ false);
+      IncrExpr = ActOnFinishFullExpr(IncrExpr.get());
     if (IncrExpr.isInvalid()) {
       Diag(RangeLoc, diag::note_for_range_invalid_iterator)
         << RangeLoc << 2 << BeginRangeRef.get()->getType() ;
@@ -2853,7 +2871,7 @@ Sema::ActOnIndirectGotoStmt(SourceLocation GotoLoc, SourceLocation StarLoc,
       return StmtError();
   }
 
-  ExprResult ExprRes = ActOnFinishFullExpr(E, /*DiscardedValue*/ false);
+  ExprResult ExprRes = ActOnFinishFullExpr(E);
   if (ExprRes.isInvalid())
     return StmtError();
   E = ExprRes.get();
@@ -3203,8 +3221,7 @@ Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
           ExpressionEvaluationContext::DiscardedStatement &&
       (HasDeducedReturnType || CurCap->HasImplicitReturnType)) {
     if (RetValExp) {
-      ExprResult ER =
-          ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
+      ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
       if (ER.isInvalid())
         return StmtError();
       RetValExp = ER.get();
@@ -3331,8 +3348,7 @@ Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
   }
 
   if (RetValExp) {
-    ExprResult ER =
-        ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
+    ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
     if (ER.isInvalid())
       return StmtError();
     RetValExp = ER.get();
@@ -3562,8 +3578,7 @@ StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
           ExpressionEvaluationContext::DiscardedStatement &&
       FnRetType->getContainedAutoType()) {
     if (RetValExp) {
-      ExprResult ER =
-          ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
+      ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
       if (ER.isInvalid())
         return StmtError();
       RetValExp = ER.get();
@@ -3657,8 +3672,7 @@ StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
       }
 
       if (RetValExp) {
-        ExprResult ER =
-            ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
+        ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
         if (ER.isInvalid())
           return StmtError();
         RetValExp = ER.get();
@@ -3737,8 +3751,7 @@ StmtResult Sema::BuildReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
     }
 
     if (RetValExp) {
-      ExprResult ER =
-          ActOnFinishFullExpr(RetValExp, ReturnLoc, /*DiscardedValue*/ false);
+      ExprResult ER = ActOnFinishFullExpr(RetValExp, ReturnLoc);
       if (ER.isInvalid())
         return StmtError();
       RetValExp = ER.get();
@@ -3791,7 +3804,7 @@ StmtResult Sema::BuildObjCAtThrowStmt(SourceLocation AtLoc, Expr *Throw) {
     if (Result.isInvalid())
       return StmtError();
 
-    Result = ActOnFinishFullExpr(Result.get(), /*DiscardedValue*/ false);
+    Result = ActOnFinishFullExpr(Result.get());
     if (Result.isInvalid())
       return StmtError();
     Throw = Result.get();
@@ -3863,7 +3876,7 @@ Sema::ActOnObjCAtSynchronizedOperand(SourceLocation atLoc, Expr *operand) {
   }
 
   // The operand to @synchronized is a full-expression.
-  return ActOnFinishFullExpr(operand, /*DiscardedValue*/ false);
+  return ActOnFinishFullExpr(operand);
 }
 
 StmtResult
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index df14768cbe81..9de4e8d654f9 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -328,7 +328,7 @@ public:
   /// other mechanism.
   ///
   /// \returns the transformed statement.
-  StmtResult TransformStmt(Stmt *S, bool DiscardedValue = false);
+  StmtResult TransformStmt(Stmt *S);
 
   /// Transform the given statement.
   ///
@@ -3269,8 +3269,8 @@ private:
                                       bool DeducibleTSTContext);
 };
 
-template <typename Derived>
-StmtResult TreeTransform<Derived>::TransformStmt(Stmt *S, bool DiscardedValue) {
+template<typename Derived>
+StmtResult TreeTransform<Derived>::TransformStmt(Stmt *S) {
   if (!S)
     return S;
 
@@ -3294,7 +3294,7 @@ StmtResult TreeTransform<Derived>::TransformStmt(Stmt *S, bool DiscardedValue) {
       if (E.isInvalid())
         return StmtError();
 
-      return getSema().ActOnExprStmt(E, DiscardedValue);
+      return getSema().ActOnExprStmt(E);
     }
   }
 
@@ -4715,8 +4715,7 @@ TreeTransform<Derived>::TransformVariableArrayType(TypeLocBuilder &TLB,
   }
   if (SizeResult.isInvalid())
     return QualType();
-  SizeResult =
-      SemaRef.ActOnFinishFullExpr(SizeResult.get(), /*DiscardedValue*/ false);
+  SizeResult = SemaRef.ActOnFinishFullExpr(SizeResult.get());
   if (SizeResult.isInvalid())
     return QualType();
 
@@ -6521,9 +6520,7 @@ TreeTransform<Derived>::TransformCompoundStmt(CompoundStmt *S,
   bool SubStmtChanged = false;
   SmallVector<Stmt*, 8> Statements;
   for (auto *B : S->body()) {
-    StmtResult Result =
-        getDerived().TransformStmt(B, !IsStmtExpr || B != S->body_back());
-
+    StmtResult Result = getDerived().TransformStmt(B);
     if (Result.isInvalid()) {
       // Immediately fail if this was a DeclStmt, since it's very
       // likely that this will cause problems for future statements.
diff --git a/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp b/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
index da94b6eb21e9..ea695c4736a3 100644
--- a/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
+++ b/lib/StaticAnalyzer/Core/BugReporterVisitors.cpp
@@ -154,6 +154,32 @@ const Expr *bugreporter::getDerefExpr(const Stmt *S) {
   return E;
 }
 
+/// Comparing internal representations of symbolic values (via
+/// SVal::operator==()) is a valid way to check if the value was updated,
+/// unless it's a LazyCompoundVal that may have a different internal
+/// representation every time it is loaded from the state. In this function we
+/// do an approximate comparison for lazy compound values, checking that they
+/// are the immediate snapshots of the tracked region's bindings within the
+/// node's respective states but not really checking that these snapshots
+/// actually contain the same set of bindings.
+bool hasVisibleUpdate(const ExplodedNode *LeftNode, SVal LeftVal,
+                      const ExplodedNode *RightNode, SVal RightVal) {
+  if (LeftVal == RightVal)
+    return true;
+
+  const auto LLCV = LeftVal.getAs<nonloc::LazyCompoundVal>();
+  if (!LLCV)
+    return false;
+
+  const auto RLCV = RightVal.getAs<nonloc::LazyCompoundVal>();
+  if (!RLCV)
+    return false;
+
+  return LLCV->getRegion() == RLCV->getRegion() &&
+    LLCV->getStore() == LeftNode->getState()->getStore() &&
+    RLCV->getStore() == RightNode->getState()->getStore();
+}
+
 //===----------------------------------------------------------------------===//
 // Definitions for bug reporter visitors.
 //===----------------------------------------------------------------------===//
@@ -1188,7 +1214,7 @@ FindLastStoreBRVisitor::VisitNode(const ExplodedNode *Succ,
     if (Succ->getState()->getSVal(R) != V)
       return nullptr;
 
-    if (Pred->getState()->getSVal(R) == V) {
+    if (hasVisibleUpdate(Pred, Pred->getState()->getSVal(R), Succ, V)) {
       Optional<PostStore> PS = Succ->getLocationAs<PostStore>();
       if (!PS || PS->getLocationValue() != R)
         return nullptr;
@@ -1209,6 +1235,7 @@ FindLastStoreBRVisitor::VisitNode(const ExplodedNode *Succ,
     // UndefinedVal.)
     if (Optional<CallEnter> CE = Succ->getLocationAs<CallEnter>()) {
       if (const auto *VR = dyn_cast<VarRegion>(R)) {
+
         const auto *Param = cast<ParmVarDecl>(VR->getDecl());
 
         ProgramStateManager &StateMgr = BRC.getStateManager();