From 229c2a388573e4e5cb5cf5f1e29e3b55949b0297 Mon Sep 17 00:00:00 2001
From: Tyler Nowicki <tnowicki@apple.com>
Date: Wed, 30 Jul 2014 20:54:33 +0000
Subject: [PATCH] Add a state variable to the loop hint attribute.
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
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This patch is necessary to support constant expressions which replaces the integer value in the loop hint attribute with an expression. The integer value was also storing the pragma’s state for options like vectorize(enable/disable) and the pragma unroll and nounroll directive. The state variable is introduced to hold the state of those options/pragmas. This moves the validation of the state (keywords) from SemaStmtAttr handler to the loop hint annotation token handler.

Reviewed by Aaron Ballman


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214333 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Basic/Attr.td                 |  25 +++--
 include/clang/Basic/DiagnosticParseKinds.td |   6 ++
 include/clang/Basic/DiagnosticSemaKinds.td  |   2 -
 include/clang/Parse/Parser.h                |   2 +-
 include/clang/Sema/LoopHint.h               |  10 +-
 lib/CodeGen/CGStmt.cpp                      |   7 +-
 lib/Parse/ParsePragma.cpp                   | 111 ++++++++++++--------
 lib/Parse/ParseStmt.cpp                     |   7 +-
 lib/Sema/SemaStmtAttr.cpp                   | 104 ++++++++----------
 test/Parser/pragma-loop.cpp                 |   3 +
 10 files changed, 157 insertions(+), 120 deletions(-)

diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index b914faf6b1..309f00aa26 100644
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -1784,12 +1784,18 @@ def Unaligned : IgnoredAttr {
 }
 
 def LoopHint : Attr {
-  /// vectorize: vectorizes loop operations if 'value != 0'.
-  /// vectorize_width: vectorize loop operations with width 'value'.
-  /// interleave: interleave multiple loop iterations if 'value != 0'.
-  /// interleave_count: interleaves 'value' loop interations.
-  /// unroll: fully unroll loop if 'value != 0'.
-  /// unroll_count: unrolls loop 'value' times.
+  /// #pragma clang loop <option> directive
+  /// vectorize: vectorizes loop operations if State == Enable.
+  /// vectorize_width: vectorize loop operations with width 'Value'.
+  /// interleave: interleave multiple loop iterations if State == Enable.
+  /// interleave_count: interleaves 'Value' loop interations.
+  /// unroll: fully unroll loop if State == Enable.
+  /// unroll_count: unrolls loop 'Value' times.
+
+  /// #pragma unroll <argument> directive
+  /// <no arg>: fully unrolls loop.
+  /// boolean: fully unrolls loop if State == Enable.
+  /// expression: unrolls loop 'Value' times.
 
   let Spellings = [Pragma<"clang", "loop">, Pragma<"", "unroll">,
                    Pragma<"", "nounroll">];
@@ -1800,6 +1806,9 @@ def LoopHint : Attr {
                            "unroll", "unroll_count"],
                           ["Vectorize", "VectorizeWidth", "Interleave", "InterleaveCount",
                            "Unroll", "UnrollCount"]>,
+              EnumArgument<"State", "LoopHintState",
+                           ["default", "enable", "disable"],
+                           ["Default", "Enable", "Disable"]>,
               DefaultIntArgument<"Value", 1>];
 
   let AdditionalMembers = [{
@@ -1841,9 +1850,9 @@ def LoopHint : Attr {
     if (option == VectorizeWidth || option == InterleaveCount ||
         option == UnrollCount)
       OS << value;
-    else if (value < 0)
+    else if (state == Default)
       return "";
-    else if (value > 0)
+    else if (state == Enable)
       OS << (option == Unroll ? "full" : "enable");
     else
       OS << "disable";
diff --git a/include/clang/Basic/DiagnosticParseKinds.td b/include/clang/Basic/DiagnosticParseKinds.td
index 38a4eac123..6b73b3b93f 100644
--- a/include/clang/Basic/DiagnosticParseKinds.td
+++ b/include/clang/Basic/DiagnosticParseKinds.td
@@ -917,10 +917,16 @@ def err_omp_immediate_directive : Error<
 def err_omp_expected_identifier_for_critical : Error<
   "expected identifier specifying the name of the 'omp critical' directive">;
 
+// Pragma support.
+def err_pragma_invalid_keyword : Error<
+  "%select{invalid|missing}0 argument; expected '%select{enable|full}1' or 'disable'">;
+
 // Pragma loop support.
 def err_pragma_loop_invalid_option : Error<
   "%select{invalid|missing}0 option%select{ %1|}0; expected vectorize, "
   "vectorize_width, interleave, interleave_count, unroll, or unroll_count">;
+def err_pragma_loop_numeric_value : Error<
+  "invalid argument; expected a positive integer value">;
 
 // Pragma unroll support.
 def warn_pragma_unroll_cuda_value_in_parens : Warning<
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 6fbd6aa816..87032b8a5c 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -541,8 +541,6 @@ def note_surrounding_namespace_starts_here : Note<
   "surrounding namespace with visibility attribute starts here">;
 def err_pragma_loop_invalid_value : Error<
   "invalid argument; expected a positive integer value">;
-def err_pragma_loop_invalid_keyword : Error<
-  "invalid argument; expected '%0' or 'disable'">;
 def err_pragma_loop_compatibility : Error<
   "%select{incompatible|duplicate}0 directives '%1' and '%2'">;
 def err_pragma_loop_precedes_nonloop : Error<
diff --git a/include/clang/Parse/Parser.h b/include/clang/Parse/Parser.h
index 3dccee7660..14b16558e6 100644
--- a/include/clang/Parse/Parser.h
+++ b/include/clang/Parse/Parser.h
@@ -525,7 +525,7 @@ private:
 
   /// \brief Handle the annotation token produced for
   /// #pragma clang loop and #pragma unroll.
-  LoopHint HandlePragmaLoopHint();
+  bool HandlePragmaLoopHint(LoopHint &Hint);
 
   /// GetLookAheadToken - This peeks ahead N tokens and returns that token
   /// without consuming any tokens.  LookAhead(0) returns 'Tok', LookAhead(1)
diff --git a/include/clang/Sema/LoopHint.h b/include/clang/Sema/LoopHint.h
index a0bc45572f..c8b2ee845e 100644
--- a/include/clang/Sema/LoopHint.h
+++ b/include/clang/Sema/LoopHint.h
@@ -29,11 +29,15 @@ struct LoopHint {
   // "#pragma unroll" and "#pragma nounroll" cases, this is identical to
   // PragmaNameLoc.
   IdentifierLoc *OptionLoc;
-  // Identifier for the hint argument.  If null, then the hint has no argument
-  // such as for "#pragma unroll".
-  IdentifierLoc *ValueLoc;
+  // Identifier for the hint state argument.  If null, then the state is
+  // default value such as for "#pragma unroll".
+  IdentifierLoc *StateLoc;
   // Expression for the hint argument if it exists, null otherwise.
   Expr *ValueExpr;
+
+  LoopHint()
+      : PragmaNameLoc(nullptr), OptionLoc(nullptr), StateLoc(nullptr),
+        ValueExpr(nullptr) {}
 };
 
 } // end namespace clang
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index d75b97ddf6..df30892e86 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -588,6 +588,7 @@ void CodeGenFunction::EmitCondBrHints(llvm::LLVMContext &Context,
       continue;
 
     LoopHintAttr::OptionType Option = LH->getOption();
+    LoopHintAttr::LoopHintState State = LH->getState();
     int ValueInt = LH->getValue();
 
     const char *MetadataName;
@@ -602,8 +603,8 @@ void CodeGenFunction::EmitCondBrHints(llvm::LLVMContext &Context,
       break;
     case LoopHintAttr::Unroll:
       // With the unroll loop hint, a non-zero value indicates full unrolling.
-      MetadataName =
-          ValueInt == 0 ? "llvm.loop.unroll.disable" : "llvm.loop.unroll.full";
+      MetadataName = State == LoopHintAttr::Disable ? "llvm.loop.unroll.disable"
+                                                    : "llvm.loop.unroll.full";
       break;
     case LoopHintAttr::UnrollCount:
       MetadataName = "llvm.loop.unroll.count";
@@ -614,7 +615,7 @@ void CodeGenFunction::EmitCondBrHints(llvm::LLVMContext &Context,
     switch (Option) {
     case LoopHintAttr::Vectorize:
     case LoopHintAttr::Interleave:
-      if (ValueInt == 1) {
+      if (State != LoopHintAttr::Disable) {
         // FIXME: In the future I will modifiy the behavior of the metadata
         // so we can enable/disable vectorization and interleaving separately.
         Name = llvm::MDString::get(Context, "llvm.loop.vectorize.enable");
diff --git a/lib/Parse/ParsePragma.cpp b/lib/Parse/ParsePragma.cpp
index 20b87d92b7..bc79e3d296 100644
--- a/lib/Parse/ParsePragma.cpp
+++ b/lib/Parse/ParsePragma.cpp
@@ -722,38 +722,65 @@ struct PragmaLoopHintInfo {
   bool HasValue;
 };
 
-LoopHint Parser::HandlePragmaLoopHint() {
+bool Parser::HandlePragmaLoopHint(LoopHint &Hint) {
   assert(Tok.is(tok::annot_pragma_loop_hint));
   PragmaLoopHintInfo *Info =
       static_cast<PragmaLoopHintInfo *>(Tok.getAnnotationValue());
+  ConsumeToken(); // The annotation token.
 
-  LoopHint Hint;
-  Hint.PragmaNameLoc =
-      IdentifierLoc::create(Actions.Context, Info->PragmaName.getLocation(),
-                            Info->PragmaName.getIdentifierInfo());
-  Hint.OptionLoc =
-      IdentifierLoc::create(Actions.Context, Info->Option.getLocation(),
-                            Info->Option.getIdentifierInfo());
-  if (Info->HasValue) {
-    Hint.Range =
-        SourceRange(Info->Option.getLocation(), Info->Value.getLocation());
-    Hint.ValueLoc =
-        IdentifierLoc::create(Actions.Context, Info->Value.getLocation(),
-                              Info->Value.getIdentifierInfo());
-
+  IdentifierInfo *PragmaNameInfo = Info->PragmaName.getIdentifierInfo();
+  Hint.PragmaNameLoc = IdentifierLoc::create(
+      Actions.Context, Info->PragmaName.getLocation(), PragmaNameInfo);
+
+  IdentifierInfo *OptionInfo = Info->Option.getIdentifierInfo();
+  Hint.OptionLoc = IdentifierLoc::create(
+      Actions.Context, Info->Option.getLocation(), OptionInfo);
+
+  // Return a valid hint if pragma unroll or nounroll were specified
+  // without an argument.
+  bool PragmaUnroll = PragmaNameInfo->getName() == "unroll";
+  bool PragmaNoUnroll = PragmaNameInfo->getName() == "nounroll";
+  if (!Info->HasValue && (PragmaUnroll || PragmaNoUnroll)) {
+    Hint.Range = Info->PragmaName.getLocation();
+    return true;
+  }
+
+  // If no option is specified the argument is assumed to be numeric.
+  bool StateOption = false;
+  if (OptionInfo)
+    StateOption = llvm::StringSwitch<bool>(OptionInfo->getName())
+                      .Case("vectorize", true)
+                      .Case("interleave", true)
+                      .Case("unroll", true)
+                      .Default(false);
+
+  // Validate the argument.
+  if (StateOption) {
+    bool OptionUnroll = OptionInfo->isStr("unroll");
+    SourceLocation StateLoc = Info->Value.getLocation();
+    IdentifierInfo *StateInfo = Info->Value.getIdentifierInfo();
+    if (!StateInfo || ((OptionUnroll ? !StateInfo->isStr("full")
+                                     : !StateInfo->isStr("enable")) &&
+                       !StateInfo->isStr("disable"))) {
+      Diag(StateLoc, diag::err_pragma_invalid_keyword)
+          << /*MissingArgument=*/false << /*FullKeyword=*/OptionUnroll;
+      return false;
+    }
+    Hint.StateLoc = IdentifierLoc::create(Actions.Context, StateLoc, StateInfo);
+  } else {
     // FIXME: We should allow non-type template parameters for the loop hint
     // value. See bug report #19610
     if (Info->Value.is(tok::numeric_constant))
       Hint.ValueExpr = Actions.ActOnNumericConstant(Info->Value).get();
-    else
-      Hint.ValueExpr = nullptr;
-  } else {
-    Hint.Range = SourceRange(Info->PragmaName.getLocation());
-    Hint.ValueLoc = nullptr;
-    Hint.ValueExpr = nullptr;
+    else {
+      Diag(Info->Value.getLocation(), diag::err_pragma_loop_numeric_value);
+      return false;
+    }
   }
 
-  return Hint;
+  Hint.Range =
+      SourceRange(Info->PragmaName.getLocation(), Info->Value.getLocation());
+  return true;
 }
 
 // #pragma GCC visibility comes in two variants:
@@ -1755,12 +1782,10 @@ void PragmaOptimizeHandler::HandlePragma(Preprocessor &PP,
 }
 
 /// \brief Parses loop or unroll pragma hint value and fills in Info.
-static bool ParseLoopHintValue(Preprocessor &PP, Token Tok, Token &PragmaName,
-                               Token &Option, bool &ValueInParens,
+static bool ParseLoopHintValue(Preprocessor &PP, Token &Tok, Token PragmaName,
+                               Token Option, bool ValueInParens,
                                PragmaLoopHintInfo &Info) {
-  ValueInParens = Tok.is(tok::l_paren);
   if (ValueInParens) {
-    PP.Lex(Tok);
     if (Tok.is(tok::r_paren)) {
       // Nothing between the parentheses.
       std::string PragmaString;
@@ -1784,13 +1809,15 @@ static bool ParseLoopHintValue(Preprocessor &PP, Token Tok, Token &PragmaName,
 
   // FIXME: Value should be stored and parsed as a constant expression.
   Token Value = Tok;
+  PP.Lex(Tok);
 
   if (ValueInParens) {
-    PP.Lex(Tok);
+    // Read ')'
     if (Tok.isNot(tok::r_paren)) {
       PP.Diag(Tok.getLocation(), diag::err_expected) << tok::r_paren;
       return true;
     }
+    PP.Lex(Tok);
   }
 
   Info.PragmaName = PragmaName;
@@ -1872,17 +1899,19 @@ void PragmaLoopHintHandler::HandlePragma(Preprocessor &PP,
           << /*MissingOption=*/false << OptionInfo;
       return;
     }
-
-    auto *Info = new (PP.getPreprocessorAllocator()) PragmaLoopHintInfo;
     PP.Lex(Tok);
-    bool ValueInParens;
-    if (ParseLoopHintValue(PP, Tok, PragmaName, Option, ValueInParens, *Info))
-      return;
 
-    if (!ValueInParens) {
-      PP.Diag(Info->Value.getLocation(), diag::err_expected) << tok::l_paren;
+    // Read '('
+    if (Tok.isNot(tok::l_paren)) {
+      PP.Diag(Tok.getLocation(), diag::err_expected) << tok::l_paren;
       return;
     }
+    PP.Lex(Tok);
+
+    auto *Info = new (PP.getPreprocessorAllocator()) PragmaLoopHintInfo;
+    if (ParseLoopHintValue(PP, Tok, PragmaName, Option, /*ValueInParens=*/true,
+                           *Info))
+      return;
 
     // Generate the loop hint token.
     Token LoopHintTok;
@@ -1891,9 +1920,6 @@ void PragmaLoopHintHandler::HandlePragma(Preprocessor &PP,
     LoopHintTok.setLocation(PragmaName.getLocation());
     LoopHintTok.setAnnotationValue(static_cast<void *>(Info));
     TokenList.push_back(LoopHintTok);
-
-    // Get next optimization option.
-    PP.Lex(Tok);
   }
 
   if (Tok.isNot(tok::eod)) {
@@ -1938,7 +1964,6 @@ void PragmaUnrollHintHandler::HandlePragma(Preprocessor &PP,
   if (Tok.is(tok::eod)) {
     // nounroll or unroll pragma without an argument.
     Info->PragmaName = PragmaName;
-    Info->Option = PragmaName;
     Info->HasValue = false;
   } else if (PragmaName.getIdentifierInfo()->getName() == "nounroll") {
     PP.Diag(Tok.getLocation(), diag::warn_pragma_extra_tokens_at_eol)
@@ -1947,9 +1972,12 @@ void PragmaUnrollHintHandler::HandlePragma(Preprocessor &PP,
   } else {
     // Unroll pragma with an argument: "#pragma unroll N" or
     // "#pragma unroll(N)".
-    bool ValueInParens;
-    if (ParseLoopHintValue(PP, Tok, PragmaName, PragmaName, ValueInParens,
-                           *Info))
+    // Read '(' if it exists.
+    bool ValueInParens = Tok.is(tok::l_paren);
+    if (ValueInParens)
+      PP.Lex(Tok);
+
+    if (ParseLoopHintValue(PP, Tok, PragmaName, Token(), ValueInParens, *Info))
       return;
 
     // In CUDA, the argument to '#pragma unroll' should not be contained in
@@ -1958,7 +1986,6 @@ void PragmaUnrollHintHandler::HandlePragma(Preprocessor &PP,
       PP.Diag(Info->Value.getLocation(),
               diag::warn_pragma_unroll_cuda_value_in_parens);
 
-    PP.Lex(Tok);
     if (Tok.isNot(tok::eod)) {
       PP.Diag(Tok.getLocation(), diag::warn_pragma_extra_tokens_at_eol)
           << "unroll";
diff --git a/lib/Parse/ParseStmt.cpp b/lib/Parse/ParseStmt.cpp
index 38723b1293..a431270d2b 100644
--- a/lib/Parse/ParseStmt.cpp
+++ b/lib/Parse/ParseStmt.cpp
@@ -1817,10 +1817,11 @@ StmtResult Parser::ParsePragmaLoopHint(StmtVector &Stmts, bool OnlyStatement,
 
   // Get loop hints and consume annotated token.
   while (Tok.is(tok::annot_pragma_loop_hint)) {
-    LoopHint Hint = HandlePragmaLoopHint();
-    ConsumeToken();
+    LoopHint Hint;
+    if (!HandlePragmaLoopHint(Hint))
+      continue;
 
-    ArgsUnion ArgHints[] = {Hint.PragmaNameLoc, Hint.OptionLoc, Hint.ValueLoc,
+    ArgsUnion ArgHints[] = {Hint.PragmaNameLoc, Hint.OptionLoc, Hint.StateLoc,
                             ArgsUnion(Hint.ValueExpr)};
     TempAttrs.addNew(Hint.PragmaNameLoc->Ident, Hint.Range, nullptr,
                      Hint.PragmaNameLoc->Loc, ArgHints, 4,
diff --git a/lib/Sema/SemaStmtAttr.cpp b/lib/Sema/SemaStmtAttr.cpp
index 595aa3656e..4cb0fde11d 100644
--- a/lib/Sema/SemaStmtAttr.cpp
+++ b/lib/Sema/SemaStmtAttr.cpp
@@ -47,13 +47,11 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
                                 SourceRange) {
   IdentifierLoc *PragmaNameLoc = A.getArgAsIdent(0);
   IdentifierLoc *OptionLoc = A.getArgAsIdent(1);
-  IdentifierInfo *OptionInfo = OptionLoc->Ident;
-  IdentifierLoc *ValueLoc = A.getArgAsIdent(2);
-  IdentifierInfo *ValueInfo = ValueLoc ? ValueLoc->Ident : nullptr;
+  IdentifierLoc *StateLoc = A.getArgAsIdent(2);
   Expr *ValueExpr = A.getArgAsExpr(3);
 
-  assert(OptionInfo && "Attribute must have valid option info.");
-
+  bool PragmaUnroll = PragmaNameLoc->Ident->getName() == "unroll";
+  bool PragmaNoUnroll = PragmaNameLoc->Ident->getName() == "nounroll";
   if (St->getStmtClass() != Stmt::DoStmtClass &&
       St->getStmtClass() != Stmt::ForStmtClass &&
       St->getStmtClass() != Stmt::CXXForRangeStmtClass &&
@@ -69,13 +67,16 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
 
   LoopHintAttr::OptionType Option;
   LoopHintAttr::Spelling Spelling;
-  if (PragmaNameLoc->Ident->getName() == "unroll") {
-    Option = ValueLoc ? LoopHintAttr::UnrollCount : LoopHintAttr::Unroll;
+  if (PragmaUnroll) {
+    Option = ValueExpr ? LoopHintAttr::UnrollCount : LoopHintAttr::Unroll;
     Spelling = LoopHintAttr::Pragma_unroll;
-  } else if (PragmaNameLoc->Ident->getName() == "nounroll") {
+  } else if (PragmaNoUnroll) {
     Option = LoopHintAttr::Unroll;
     Spelling = LoopHintAttr::Pragma_nounroll;
   } else {
+    assert(OptionLoc && OptionLoc->Ident &&
+           "Attribute must have valid option info.");
+    IdentifierInfo *OptionInfo = OptionLoc->Ident;
     Option = llvm::StringSwitch<LoopHintAttr::OptionType>(OptionInfo->getName())
                  .Case("vectorize", LoopHintAttr::Vectorize)
                  .Case("vectorize_width", LoopHintAttr::VectorizeWidth)
@@ -87,35 +88,10 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
     Spelling = LoopHintAttr::Pragma_clang_loop;
   }
 
-  int ValueInt = -1;
-  if (Option == LoopHintAttr::Unroll &&
-      Spelling == LoopHintAttr::Pragma_unroll) {
-    if (ValueInfo)
-      ValueInt = (ValueInfo->isStr("disable") ? 0 : 1);
-  } else if (Option == LoopHintAttr::Unroll &&
-             Spelling == LoopHintAttr::Pragma_nounroll) {
-    ValueInt = 0;
-  } else if (Option == LoopHintAttr::Vectorize ||
-             Option == LoopHintAttr::Interleave ||
-             Option == LoopHintAttr::Unroll) {
-    // Unrolling uses the keyword "full" rather than "enable" to indicate full
-    // unrolling.
-    const char *TrueKeyword =
-        Option == LoopHintAttr::Unroll ? "full" : "enable";
-    if (!ValueInfo) {
-      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword)
-          << TrueKeyword;
-      return nullptr;
-    }
-    if (ValueInfo->isStr("disable"))
-      ValueInt = 0;
-    else if (ValueInfo->getName() == TrueKeyword)
-      ValueInt = 1;
-    else {
-      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword)
-          << TrueKeyword;
-      return nullptr;
-    }
+  int ValueInt = 1;
+  LoopHintAttr::LoopHintState State = LoopHintAttr::Default;
+  if (PragmaNoUnroll) {
+    State = LoopHintAttr::Disable;
   } else if (Option == LoopHintAttr::VectorizeWidth ||
              Option == LoopHintAttr::InterleaveCount ||
              Option == LoopHintAttr::UnrollCount) {
@@ -124,28 +100,39 @@ static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
     llvm::APSInt ValueAPS;
     if (!ValueExpr || !ValueExpr->isIntegerConstantExpr(ValueAPS, S.Context) ||
         (ValueInt = ValueAPS.getSExtValue()) < 1) {
-      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_value);
+      S.Diag(A.getLoc(), diag::err_pragma_loop_invalid_value);
       return nullptr;
     }
-  } else
-    llvm_unreachable("Unknown loop hint option");
+  } else if (Option == LoopHintAttr::Vectorize ||
+             Option == LoopHintAttr::Interleave ||
+             Option == LoopHintAttr::Unroll) {
+    // Default state is assumed if StateLoc is not specified, such as with
+    // '#pragma unroll'.
+    if (StateLoc && StateLoc->Ident) {
+      if (StateLoc->Ident->isStr("disable"))
+        State = LoopHintAttr::Disable;
+      else
+        State = LoopHintAttr::Enable;
+    }
+  }
 
-  return LoopHintAttr::CreateImplicit(S.Context, Spelling, Option, ValueInt,
-                                      A.getRange());
+  return LoopHintAttr::CreateImplicit(S.Context, Spelling, Option, State,
+                                      ValueInt, A.getRange());
 }
 
-static void CheckForIncompatibleAttributes(
-    Sema &S, const SmallVectorImpl<const Attr *> &Attrs) {
-  // There are 3 categories of loop hints attributes: vectorize, interleave, and
-  // unroll. Each comes in two variants: a boolean form and a numeric form.  The
-  // boolean hints selectively enables/disables the transformation for the loop
-  // (for unroll, a nonzero value indicates full unrolling rather than enabling
-  // the transformation).  The numeric hint provides an integer hint (for
-  // example, unroll count) to the transformer. The following array accumulates
-  // the hints encountered while iterating through the attributes to check for
-  // compatibility.
+static void
+CheckForIncompatibleAttributes(Sema &S,
+                               const SmallVectorImpl<const Attr *> &Attrs) {
+  // There are 3 categories of loop hints attributes: vectorize, interleave,
+  // and unroll. Each comes in two variants: a state form and a numeric form.
+  // The state form selectively defaults/enables/disables the transformation
+  // for the loop (for unroll, default indicates full unrolling rather than
+  // enabling the transformation).  The numeric form form provides an integer
+  // hint (for example, unroll count) to the transformer. The following array
+  // accumulates the hints encountered while iterating through the attributes
+  // to check for compatibility.
   struct {
-    const LoopHintAttr *EnableAttr;
+    const LoopHintAttr *StateAttr;
     const LoopHintAttr *NumericAttr;
   } HintAttrs[] = {{nullptr, nullptr}, {nullptr, nullptr}, {nullptr, nullptr}};
 
@@ -179,8 +166,8 @@ static void CheckForIncompatibleAttributes(
     if (Option == LoopHintAttr::Vectorize ||
         Option == LoopHintAttr::Interleave || Option == LoopHintAttr::Unroll) {
       // Enable|disable hint.  For example, vectorize(enable).
-      PrevAttr = CategoryState.EnableAttr;
-      CategoryState.EnableAttr = LH;
+      PrevAttr = CategoryState.StateAttr;
+      CategoryState.StateAttr = LH;
     } else {
       // Numeric hint.  For example, vectorize_width(8).
       PrevAttr = CategoryState.NumericAttr;
@@ -195,14 +182,15 @@ static void CheckForIncompatibleAttributes(
           << /*Duplicate=*/true << PrevAttr->getDiagnosticName(Policy)
           << LH->getDiagnosticName(Policy);
 
-    if (CategoryState.EnableAttr && CategoryState.NumericAttr &&
-        (Category == Unroll || !CategoryState.EnableAttr->getValue())) {
+    if (CategoryState.StateAttr && CategoryState.NumericAttr &&
+        (Category == Unroll ||
+         CategoryState.StateAttr->getState() == LoopHintAttr::Disable)) {
       // Disable hints are not compatible with numeric hints of the same
       // category.  As a special case, numeric unroll hints are also not
       // compatible with "enable" form of the unroll pragma, unroll(full).
       S.Diag(OptionLoc, diag::err_pragma_loop_compatibility)
           << /*Duplicate=*/false
-          << CategoryState.EnableAttr->getDiagnosticName(Policy)
+          << CategoryState.StateAttr->getDiagnosticName(Policy)
           << CategoryState.NumericAttr->getDiagnosticName(Policy);
     }
   }
diff --git a/test/Parser/pragma-loop.cpp b/test/Parser/pragma-loop.cpp
index ac07af9bc7..742a5d71e0 100644
--- a/test/Parser/pragma-loop.cpp
+++ b/test/Parser/pragma-loop.cpp
@@ -83,6 +83,9 @@ void test(int *List, int Length) {
     List[i] = i;
   }
 
+/* expected-error {{expected ')'}} */ #pragma clang loop vectorize_width(1 +) 1
+/* expected-warning {{extra tokens at end of '#pragma clang loop'}} */ #pragma clang loop vectorize_width(1) +1
+
 /* expected-error {{invalid argument; expected a positive integer value}} */ #pragma clang loop vectorize_width(badvalue)
 /* expected-error {{invalid argument; expected a positive integer value}} */ #pragma clang loop interleave_count(badvalue)
 /* expected-error {{invalid argument; expected a positive integer value}} */ #pragma clang loop unroll_count(badvalue)
-- 
2.40.0