[PATCH] #pragma vectorize

Aaron Ballman aaron at aaronballman.com
Tue Jun 3 06:35:21 PDT 2014


Minor nits below, but otherwise LGTM! Thank you for all of your hard
work on this!

> Index: include/clang/Basic/Attr.td
> ===================================================================
> --- include/clang/Basic/Attr.td (revision 210052)
> +++ include/clang/Basic/Attr.td (working copy)
> @@ -1760,3 +1760,50 @@
>  def Unaligned : IgnoredAttr {
>    let Spellings = [Keyword<"__unaligned">];
>  }
> +
> +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.
> +
> +  /// FIXME: Add Pragma spelling to tablegen and
> +  /// use it here.
> +  let Spellings = [Keyword<"loop">];
> +
> +  /// State of the loop optimization specified by the spelling.
> +  let Args = [EnumArgument<"Option", "OptionType",
> +                          ["vectorize", "vectorize_width", "interleave", "interleave_count"],
> +                          ["Vectorize", "VectorizeWidth", "Interleave", "InterleaveCount"]>,
> +              DefaultIntArgument<"Value", 1>];
> +
> +  let AdditionalMembers = [{
> +  static StringRef getOptionName(int Option) {
> +    switch(Option) {
> +    case Vectorize: return "vectorize";
> +    case VectorizeWidth: return "vectorize_width";
> +    case Interleave: return "interleave";
> +    case InterleaveCount: return "interleave_count";
> +    }
> +    llvm_unreachable("Unhandled LoopHint option.");
> +  }
> +
> +  static StringRef getValueName(int Value) {
> +    if (Value)
> +      return "enable";
> +    return "disable";
> +  }
> +
> +  // FIXME: Modify pretty printer to print this pragma.
> +  void print(raw_ostream &OS, const PrintingPolicy &Policy) const {
> +    OS << "#pragma clang loop " << getOptionName(option) << "(";
> +    if (option == VectorizeWidth || option == InterleaveCount)
> +      OS << value;
> +    else
> +      OS << getValueName(value);
> +    OS << ")\n";
> +  }
> +  }];
> +
> +  let Documentation = [Undocumented];
> +}
> Index: include/clang/Basic/DiagnosticParseKinds.td
> ===================================================================
> --- include/clang/Basic/DiagnosticParseKinds.td (revision 210052)
> +++ include/clang/Basic/DiagnosticParseKinds.td (working copy)
> @@ -892,6 +892,10 @@
>    "unexpected OpenMP clause '%0' in directive '#pragma omp %1'">;
>  def err_omp_more_one_clause : Error<
>    "directive '#pragma omp %0' cannot contain more than one '%1' clause">;
> +
> +// Pragma loop support.
> +def err_pragma_loop_invalid_option : Error<
> +  "%select{invalid|missing}0 option%select{ %1|}0; expected vectorize, vectorize_width, interleave, or interleave_count">;
>  } // end of Parse Issue category.
>
>  let CategoryName = "Modules Issue" in {
> Index: include/clang/Basic/DiagnosticSemaKinds.td
> ===================================================================
> --- include/clang/Basic/DiagnosticSemaKinds.td (revision 210052)
> +++ include/clang/Basic/DiagnosticSemaKinds.td (working copy)
> @@ -542,6 +542,15 @@
>    "#pragma visibility pop with no matching #pragma visibility push">;
>  def note_surrounding_namespace_starts_here : Note<
>    "surrounding namespace with visibility attribute starts here">;
> +def err_pragma_loop_invalid_value : Error<
> +  "%select{invalid|missing}0 value%select{ %1|}0; expected a positive integer value">;
> +def err_pragma_loop_invalid_keyword : Error<
> +  "%select{invalid|missing}0 keyword%select{ %1|}0; expected 'enable' or 'disable'">;
> +def err_pragma_loop_compatibility : Error<
> +  "%select{incompatible|duplicate}0 directives '%1(%2)' and '%3(%4)'">;
> +def err_pragma_loop_precedes_nonloop : Error<
> +  "expected a for, while, or do-while loop to follow the '#pragma clang loop' "
> +  "directive">;
>
>  /// Objective-C parser diagnostics
>  def err_duplicate_class_def : Error<
> Index: include/clang/Basic/TokenKinds.def
> ===================================================================
> --- include/clang/Basic/TokenKinds.def (revision 210052)
> +++ include/clang/Basic/TokenKinds.def (working copy)
> @@ -701,6 +701,11 @@
>  ANNOTATION(pragma_openmp)
>  ANNOTATION(pragma_openmp_end)
>
> +// Annotations for loop pragma directives #pragma clang loop ...
> +// The lexer produces these so that they only take effect when the parser
> +// handles #pragma loop ... directives.
> +ANNOTATION(pragma_loop_hint)
> +
>  // Annotations for module import translated from #include etc.
>  ANNOTATION(module_include)
>  ANNOTATION(module_begin)
> Index: include/clang/Parse/Parser.h
> ===================================================================
> --- include/clang/Parse/Parser.h (revision 210052)
> +++ include/clang/Parse/Parser.h (working copy)
> @@ -20,6 +20,7 @@
>  #include "clang/Lex/CodeCompletionHandler.h"
>  #include "clang/Lex/Preprocessor.h"
>  #include "clang/Sema/DeclSpec.h"
> +#include "clang/Sema/LoopHint.h"
>  #include "clang/Sema/Sema.h"
>  #include "llvm/ADT/SmallVector.h"
>  #include "llvm/Support/Compiler.h"
> @@ -161,6 +162,7 @@
>    std::unique_ptr<PragmaHandler> MSCodeSeg;
>    std::unique_ptr<PragmaHandler> MSSection;
>    std::unique_ptr<PragmaHandler> OptimizeHandler;
> +  std::unique_ptr<PragmaHandler> LoopHintHandler;
>
>    std::unique_ptr<CommentHandler> CommentSemaHandler;
>
> @@ -519,6 +521,10 @@
>    /// #pragma clang __debug captured
>    StmtResult HandlePragmaCaptured();
>
> +  /// \brief Handle the annotation token produced for
> +  /// #pragma vectorize...
> +  LoopHint HandlePragmaLoopHint();
> +
>    /// GetLookAheadToken - This peeks ahead N tokens and returns that token
>    /// without consuming any tokens.  LookAhead(0) returns 'Tok', LookAhead(1)
>    /// returns the token after Tok, etc.
> @@ -1601,6 +1607,9 @@
>    StmtResult ParseReturnStatement();
>    StmtResult ParseAsmStatement(bool &msAsm);
>    StmtResult ParseMicrosoftAsmStatement(SourceLocation AsmLoc);
> +  StmtResult ParsePragmaLoopHint(StmtVector &Stmts, bool OnlyStatement,
> +                                 SourceLocation *TrailingElseLoc,
> +                                 ParsedAttributesWithRange &Attrs);
>
>    /// \brief Describes the behavior that should be taken for an __if_exists
>    /// block.
> Index: include/clang/Sema/LoopHint.h
> ===================================================================
> --- include/clang/Sema/LoopHint.h (revision 0)
> +++ include/clang/Sema/LoopHint.h (working copy)
> @@ -0,0 +1,31 @@
> +//===--- LoopHint.h - Types for LoopHint ------------------------*- C++ -*-===//
> +//
> +//                     The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +#ifndef LLVM_CLANG_SEMA_LOOPHINT_H
> +#define LLVM_CLANG_SEMA_LOOPHINT_H
> +
> +#include "clang/Basic/IdentifierTable.h"
> +#include "clang/Basic/SourceLocation.h"
> +#include "clang/Sema/AttributeList.h"
> +#include "clang/Sema/Ownership.h"
> +
> +namespace clang {
> +
> +/// \brief Loop hint specified by a pragma loop directive.
> +struct LoopHint {
> +  SourceRange Range;
> +  Expr *ValueExpr;
> +  IdentifierLoc *LoopLoc;
> +  IdentifierLoc *ValueLoc;
> +  IdentifierLoc *OptionLoc;
> +};
> +
> +} // end namespace clang
> +
> +#endif // LLVM_CLANG_SEMA_LOOPHINT_H
> Index: lib/AST/StmtPrinter.cpp
> ===================================================================
> --- lib/AST/StmtPrinter.cpp (revision 210052)
> +++ lib/AST/StmtPrinter.cpp (working copy)
> @@ -168,8 +168,22 @@
>  }
>
>  void StmtPrinter::VisitAttributedStmt(AttributedStmt *Node) {
> -  for (const auto *Attr : Node->getAttrs())
> -    Attr->printPretty(OS, Policy);
> +  std::string raw_attr_os;
> +  llvm::raw_string_ostream AttrOS(raw_attr_os);
> +  for (const auto *Attr : Node->getAttrs()) {
> +    // FIXME: This hack will be removed when printPretty
> +    // has been modified to print pretty pragmas
> +    if (const LoopHintAttr *LHA = dyn_cast<LoopHintAttr>(Attr)) {
> +      LHA->print(OS, Policy);
> +    } else
> +      Attr->printPretty(AttrOS, Policy);
> +  }
> +
> +  // Print attributes after pragmas.
> +  StringRef AttrStr = AttrOS.str();
> +  if (!AttrStr.empty())
> +    OS << AttrStr;
> +
>    PrintStmt(Node->getSubStmt(), 0);
>  }
>
> Index: lib/CodeGen/CGStmt.cpp
> ===================================================================
> --- lib/CodeGen/CGStmt.cpp (revision 210052)
> +++ lib/CodeGen/CGStmt.cpp (working copy)
> @@ -18,6 +18,7 @@
>  #include "clang/AST/StmtVisitor.h"
>  #include "clang/Basic/PrettyStackTrace.h"
>  #include "clang/Basic/TargetInfo.h"
> +#include "clang/Sema/LoopHint.h"
>  #include "clang/Sema/SemaDiagnostic.h"
>  #include "llvm/ADT/StringExtras.h"
>  #include "llvm/IR/CallSite.h"
> @@ -398,7 +399,23 @@
>  }
>
>  void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
> -  EmitStmt(S.getSubStmt());
> +  const Stmt *SubStmt = S.getSubStmt();
> +  switch (SubStmt->getStmtClass()) {
> +  case Stmt::DoStmtClass:
> +    EmitDoStmt(cast<DoStmt>(*SubStmt), S.getAttrs());
> +    break;
> +  case Stmt::ForStmtClass:
> +    EmitForStmt(cast<ForStmt>(*SubStmt), S.getAttrs());
> +    break;
> +  case Stmt::WhileStmtClass:
> +    EmitWhileStmt(cast<WhileStmt>(*SubStmt), S.getAttrs());
> +    break;
> +  case Stmt::CXXForRangeStmtClass:
> +    EmitCXXForRangeStmt(cast<CXXForRangeStmt>(*SubStmt), S.getAttrs());
> +    break;
> +  default:
> +    EmitStmt(SubStmt);
> +  }
>  }
>
>  void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
> @@ -504,7 +521,70 @@
>    EmitBlock(ContBlock, true);
>  }
>
> -void CodeGenFunction::EmitWhileStmt(const WhileStmt &S) {
> +void CodeGenFunction::EmitCondBrHints(llvm::LLVMContext &Context,
> +                                      llvm::BranchInst *CondBr,
> +                                      const ArrayRef<const Attr *> &Attrs) {
> +  // Return if there are no hints.
> +  if (Attrs.empty())
> +    return;
> +
> +  // Add vectorize hints to the metadata on the conditional branch.
> +  SmallVector<llvm::Value *, 2> Metadata(1);
> +  for (auto Attr : Attrs) {

const auto *Attr instead of just auto.

> +    const LoopHintAttr *LH = dyn_cast<LoopHintAttr>(Attr);
> +
> +    // Skip non loop hint attributes
> +    if (!LH)
> +      continue;
> +
> +    LoopHintAttr::OptionType Option = LH->getOption();
> +    int ValueInt = LH->getValue();
> +
> +    // FIXME: In the future I will modifiy the behavior of the metadata
> +    // so we can enable/disable vectorization and interleaving separately.
> +    llvm::Value *Value;
> +    llvm::MDString *Name;
> +    const char *MetadataNames[] = {
> +        "llvm.vectorizer.width", "llvm.vectorizer.width",
> +        "llvm.vectorizer.unroll", "llvm.vectorizer.unroll"};
> +
> +    switch (Option) {
> +    case LoopHintAttr::Vectorize:
> +    case LoopHintAttr::Interleave:
> +      if (ValueInt == 1) {
> +        Name = llvm::MDString::get(Context, "llvm.vectorizer.enable");
> +        Value = Builder.getTrue();
> +        break;
> +      }
> +      // Vectorization/interleaving is disabled, set width/count to 1.
> +      ValueInt = 1;
> +    // Fallthrough.

We should add [[clang::fallthrough]] to Compiler.h and use it here. :-)

> +    case LoopHintAttr::VectorizeWidth:
> +    case LoopHintAttr::InterleaveCount:
> +      Name = llvm::MDString::get(Context, MetadataNames[Option]);
> +      Value = llvm::ConstantInt::get(Int32Ty, ValueInt);
> +      break;
> +    }
> +
> +    SmallVector<llvm::Value *, 2> OpValues;
> +    OpValues.push_back(Name);
> +    OpValues.push_back(Value);
> +
> +    // Set or overwrite metadata indicated by Name.
> +    Metadata.push_back(llvm::MDNode::get(Context, OpValues));
> +  }
> +
> +  if (!Metadata.empty()) {
> +    // Add llvm.loop MDNode to CondBr.
> +    llvm::MDNode *LoopID = llvm::MDNode::get(Context, Metadata);
> +    LoopID->replaceOperandWith(0, LoopID); // First op points to itself.
> +
> +    CondBr->setMetadata("llvm.loop", LoopID);
> +  }
> +}
> +
> +void CodeGenFunction::EmitWhileStmt(const WhileStmt &S,
> +                                    const ArrayRef<const Attr *> &WhileAttrs) {
>    RegionCounter Cnt = getPGORegionCounter(&S);
>
>    // Emit the header for the loop, which will also become
> @@ -551,13 +631,17 @@
>      llvm::BasicBlock *ExitBlock = LoopExit.getBlock();
>      if (ConditionScope.requiresCleanups())
>        ExitBlock = createBasicBlock("while.exit");
> -    Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock,
> -                         PGO.createLoopWeights(S.getCond(), Cnt));
> +    llvm::BranchInst *CondBr =
> +        Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock,
> +                             PGO.createLoopWeights(S.getCond(), Cnt));
>
>      if (ExitBlock != LoopExit.getBlock()) {
>        EmitBlock(ExitBlock);
>        EmitBranchThroughCleanup(LoopExit);
>      }
> +
> +    // Attach metadata to loop body conditional branch.
> +    EmitCondBrHints(LoopBody->getContext(), CondBr, WhileAttrs);
>    }
>
>    // Emit the loop body.  We have to emit this in a cleanup scope
> @@ -588,7 +672,8 @@
>      SimplifyForwardingBlocks(LoopHeader.getBlock());
>  }
>
> -void CodeGenFunction::EmitDoStmt(const DoStmt &S) {
> +void CodeGenFunction::EmitDoStmt(const DoStmt &S,
> +                                 const ArrayRef<const Attr *> &DoAttrs) {
>    JumpDest LoopExit = getJumpDestInCurrentScope("do.end");
>    JumpDest LoopCond = getJumpDestInCurrentScope("do.cond");
>
> @@ -628,10 +713,15 @@
>        EmitBoolCondBranch = false;
>
>    // As long as the condition is true, iterate the loop.
> -  if (EmitBoolCondBranch)
> -    Builder.CreateCondBr(BoolCondVal, LoopBody, LoopExit.getBlock(),
> -                         PGO.createLoopWeights(S.getCond(), Cnt));
> +  if (EmitBoolCondBranch) {
> +    llvm::BranchInst *CondBr =
> +        Builder.CreateCondBr(BoolCondVal, LoopBody, LoopExit.getBlock(),
> +                             PGO.createLoopWeights(S.getCond(), Cnt));
>
> +    // Attach metadata to loop body conditional branch.
> +    EmitCondBrHints(LoopBody->getContext(), CondBr, DoAttrs);
> +  }
> +
>    LoopStack.pop();
>
>    // Emit the exit block.
> @@ -643,7 +733,8 @@
>      SimplifyForwardingBlocks(LoopCond.getBlock());
>  }
>
> -void CodeGenFunction::EmitForStmt(const ForStmt &S) {
> +void CodeGenFunction::EmitForStmt(const ForStmt &S,
> +                                  const ArrayRef<const Attr *> &ForAttrs) {
>    JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
>
>    RunCleanupsScope ForScope(*this);
> @@ -699,9 +790,13 @@
>      // C99 6.8.5p2/p4: The first substatement is executed if the expression
>      // compares unequal to 0.  The condition must be a scalar type.
>      llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
> -    Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock,
> -                         PGO.createLoopWeights(S.getCond(), Cnt));
> +    llvm::BranchInst *CondBr =
> +        Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock,
> +                             PGO.createLoopWeights(S.getCond(), Cnt));
>
> +    // Attach metadata to loop body conditional branch.
> +    EmitCondBrHints(ForBody->getContext(), CondBr, ForAttrs);
> +
>      if (ExitBlock != LoopExit.getBlock()) {
>        EmitBlock(ExitBlock);
>        EmitBranchThroughCleanup(LoopExit);
> @@ -743,7 +838,9 @@
>    EmitBlock(LoopExit.getBlock(), true);
>  }
>
> -void CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S) {
> +void
> +CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
> +                                     const ArrayRef<const Attr *> &ForAttrs) {
>    JumpDest LoopExit = getJumpDestInCurrentScope("for.end");
>
>    RunCleanupsScope ForScope(*this);
> @@ -778,9 +875,12 @@
>    // The body is executed if the expression, contextually converted
>    // to bool, is true.
>    llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond());
> -  Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock,
> -                       PGO.createLoopWeights(S.getCond(), Cnt));
> +  llvm::BranchInst *CondBr = Builder.CreateCondBr(
> +      BoolCondVal, ForBody, ExitBlock, PGO.createLoopWeights(S.getCond(), Cnt));
>
> +  // Attach metadata to loop body conditional branch.
> +  EmitCondBrHints(ForBody->getContext(), CondBr, ForAttrs);
> +
>    if (ExitBlock != LoopExit.getBlock()) {
>      EmitBlock(ExitBlock);
>      EmitBranchThroughCleanup(LoopExit);
> Index: lib/CodeGen/CodeGenFunction.h
> ===================================================================
> --- lib/CodeGen/CodeGenFunction.h (revision 210052)
> +++ lib/CodeGen/CodeGenFunction.h (working copy)
> @@ -1856,9 +1856,14 @@
>    void EmitGotoStmt(const GotoStmt &S);
>    void EmitIndirectGotoStmt(const IndirectGotoStmt &S);
>    void EmitIfStmt(const IfStmt &S);
> -  void EmitWhileStmt(const WhileStmt &S);
> -  void EmitDoStmt(const DoStmt &S);
> -  void EmitForStmt(const ForStmt &S);
> +
> +  void EmitCondBrHints(llvm::LLVMContext &Context, llvm::BranchInst *CondBr,
> +                       const ArrayRef<const Attr *> &Attrs);
> +  void EmitWhileStmt(const WhileStmt &S,
> +                     const ArrayRef<const Attr *> &Attrs = None);
> +  void EmitDoStmt(const DoStmt &S, const ArrayRef<const Attr *> &Attrs = None);
> +  void EmitForStmt(const ForStmt &S,
> +                   const ArrayRef<const Attr *> &Attrs = None);
>    void EmitReturnStmt(const ReturnStmt &S);
>    void EmitDeclStmt(const DeclStmt &S);
>    void EmitBreakStmt(const BreakStmt &S);
> @@ -1882,7 +1887,8 @@
>
>    void EmitCXXTryStmt(const CXXTryStmt &S);
>    void EmitSEHTryStmt(const SEHTryStmt &S);
> -  void EmitCXXForRangeStmt(const CXXForRangeStmt &S);
> +  void EmitCXXForRangeStmt(const CXXForRangeStmt &S,
> +                           const ArrayRef<const Attr *> &Attrs = None);
>
>    llvm::Function *EmitCapturedStmt(const CapturedStmt &S, CapturedRegionKind K);
>    llvm::Function *GenerateCapturedStmtFunction(const CapturedDecl *CD,
> Index: lib/Parse/ParsePragma.cpp
> ===================================================================
> --- lib/Parse/ParsePragma.cpp (revision 210052)
> +++ lib/Parse/ParsePragma.cpp (working copy)
> @@ -15,6 +15,7 @@
>  #include "clang/Lex/Preprocessor.h"
>  #include "clang/Parse/ParseDiagnostic.h"
>  #include "clang/Parse/Parser.h"
> +#include "clang/Sema/LoopHint.h"
>  #include "clang/Sema/Scope.h"
>  #include "llvm/ADT/StringSwitch.h"
>  using namespace clang;
> @@ -141,6 +142,12 @@
>    Sema &Actions;
>  };
>
> +struct PragmaLoopHintHandler : public PragmaHandler {
> +  PragmaLoopHintHandler() : PragmaHandler("loop") {}
> +  void HandlePragma(Preprocessor &PP, PragmaIntroducerKind Introducer,
> +                    Token &FirstToken) override;
> +};
> +
>  }  // end namespace
>
>  void Parser::initializePragmaHandlers() {
> @@ -208,6 +215,9 @@
>
>    OptimizeHandler.reset(new PragmaOptimizeHandler(Actions));
>    PP.AddPragmaHandler("clang", OptimizeHandler.get());
> +
> +  LoopHintHandler.reset(new PragmaLoopHintHandler());
> +  PP.AddPragmaHandler("clang", LoopHintHandler.get());
>  }
>
>  void Parser::resetPragmaHandlers() {
> @@ -265,6 +275,9 @@
>
>    PP.RemovePragmaHandler("clang", OptimizeHandler.get());
>    OptimizeHandler.reset();
> +
> +  PP.RemovePragmaHandler("clang", LoopHintHandler.get());
> +  LoopHintHandler.reset();
>  }
>
>  /// \brief Handle the annotation token produced for #pragma unused(...)
> @@ -586,6 +599,40 @@
>        DiagnosticsEngine::Error, "'#pragma %0' not implemented.");
>  }
>
> +struct PragmaLoopHintInfo {
> +  Token Loop;
> +  Token Value;
> +  Token Option;
> +};
> +
> +LoopHint Parser::HandlePragmaLoopHint() {
> +  assert(Tok.is(tok::annot_pragma_loop_hint));
> +  PragmaLoopHintInfo *Info =
> +      static_cast<PragmaLoopHintInfo *>(Tok.getAnnotationValue());
> +
> +  LoopHint Hint;
> +  Hint.LoopLoc =
> +      IdentifierLoc::create(Actions.Context, Info->Loop.getLocation(),
> +                            Info->Loop.getIdentifierInfo());
> +  Hint.OptionLoc =
> +      IdentifierLoc::create(Actions.Context, Info->Option.getLocation(),
> +                            Info->Option.getIdentifierInfo());
> +  Hint.ValueLoc =
> +      IdentifierLoc::create(Actions.Context, Info->Value.getLocation(),
> +                            Info->Value.getIdentifierInfo());
> +  Hint.Range =
> +      SourceRange(Info->Option.getLocation(), Info->Value.getLocation());
> +
> +  // FIXME: We should support 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;
> +
> +  return Hint;
> +}
> +
>  // #pragma GCC visibility comes in two variants:
>  //   'push' '(' [visibility] ')'
>  //   'pop'
> @@ -1584,3 +1631,110 @@
>
>    Actions.ActOnPragmaOptimize(IsOn, FirstToken.getLocation());
>  }
> +
> +/// \brief Handle the \#pragma clang loop directive.
> +///  #pragma clang 'loop' loop-hints
> +///
> +///  loop-hints:
> +///    loop-hint loop-hints[opt]
> +///
> +///  loop-hint:
> +///    'vectorize' '(' loop-hint-keyword ')'
> +///    'interleave' '(' loop-hint-keyword ')'
> +///    'vectorize_width' '(' loop-hint-value ')'
> +///    'interleave_count' '(' loop-hint-value ')'
> +///
> +///  loop-hint-keyword:
> +///    'enable'
> +///    'disable'
> +///
> +///  loop-hint-value:
> +///    constant-expression
> +///
> +/// Specifying vectorize(enable) or vectorize_width(_value_) instructs llvm to
> +/// try vectorizing the instructions of the loop it precedes. Specifying
> +/// interleave(enable) or interleave_count(_value_) instructs llvm to try
> +/// interleaving multiple iterations of the loop it precedes. The width of the
> +/// vector instructions is specified by vectorize_width() and the number of
> +/// interleaved loop iterations is specified by interleave_count(). Specifying a
> +/// value of 1 effectively disables vectorization/interleaving, even if it is
> +/// possible and profitable, and 0 is invalid. The loop vectorizer currently
> +/// only works on inner loops.
> +///
> +void PragmaLoopHintHandler::HandlePragma(Preprocessor &PP,
> +                                         PragmaIntroducerKind Introducer,
> +                                         Token &Tok) {
> +  Token Loop = Tok;
> +  SmallVector<Token, 1> TokenList;
> +
> +  // Lex the optimization option and verify it is an identifier.
> +  PP.Lex(Tok);
> +  if (Tok.isNot(tok::identifier)) {
> +    PP.Diag(Tok.getLocation(), diag::err_pragma_loop_invalid_option)
> +        << /*MissingOption=*/true << "";
> +    return;
> +  }
> +
> +  while (Tok.is(tok::identifier)) {
> +    Token Option = Tok;
> +    IdentifierInfo *OptionInfo = Tok.getIdentifierInfo();
> +
> +    if (!OptionInfo->isStr("vectorize") && !OptionInfo->isStr("interleave") &&
> +        !OptionInfo->isStr("vectorize_width") &&
> +        !OptionInfo->isStr("interleave_count")) {
> +      PP.Diag(Tok.getLocation(), diag::err_pragma_loop_invalid_option)
> +          << /*MissingOption=*/false << OptionInfo;
> +      return;
> +    }
> +
> +    // Read '('
> +    PP.Lex(Tok);
> +    if (Tok.isNot(tok::l_paren)) {
> +      PP.Diag(Tok.getLocation(), diag::err_expected) << tok::l_paren;
> +      return;
> +    }
> +
> +    // FIXME: All tokens between '(' and ')' should be stored and parsed as a
> +    // constant expression.
> +    PP.Lex(Tok);
> +    Token Value;
> +    if (Tok.is(tok::identifier) || Tok.is(tok::numeric_constant))
> +      Value = Tok;
> +
> +    // Read ')'
> +    PP.Lex(Tok);
> +    if (Tok.isNot(tok::r_paren)) {
> +      PP.Diag(Tok.getLocation(), diag::err_expected) << tok::r_paren;
> +      return;
> +    }
> +
> +    // Get next optimization option.
> +    PP.Lex(Tok);
> +
> +    auto *Info = new (PP.getPreprocessorAllocator()) PragmaLoopHintInfo;
> +    Info->Loop = Loop;
> +    Info->Option = Option;
> +    Info->Value = Value;
> +
> +    // Generate the vectorization hint token.
> +    Token LoopHintTok;
> +    LoopHintTok.startToken();
> +    LoopHintTok.setKind(tok::annot_pragma_loop_hint);
> +    LoopHintTok.setLocation(Loop.getLocation());
> +    LoopHintTok.setAnnotationValue(static_cast<void *>(Info));
> +    TokenList.push_back(LoopHintTok);
> +  }
> +
> +  if (Tok.isNot(tok::eod)) {
> +    PP.Diag(Tok.getLocation(), diag::warn_pragma_extra_tokens_at_eol)
> +        << "clang loop";
> +    return;
> +  }
> +
> +  Token *TokenArray = new Token[TokenList.size()];
> +  std::copy(TokenList.begin(), TokenList.end(), TokenArray);
> +
> +  PP.EnterTokenStream(TokenArray, TokenList.size(),
> +                      /*DisableMacroExpansion=*/false,
> +                      /*OwnsTokens=*/true);
> +}
> Index: lib/Parse/ParseStmt.cpp
> ===================================================================
> --- lib/Parse/ParseStmt.cpp (revision 210052)
> +++ lib/Parse/ParseStmt.cpp (working copy)
> @@ -15,11 +15,13 @@
>  #include "clang/Parse/Parser.h"
>  #include "RAIIObjectsForParser.h"
>  #include "clang/AST/ASTContext.h"
> +#include "clang/Basic/Attributes.h"
>  #include "clang/Basic/Diagnostic.h"
>  #include "clang/Basic/PrettyStackTrace.h"
>  #include "clang/Basic/SourceManager.h"
>  #include "clang/Basic/TargetInfo.h"
>  #include "clang/Sema/DeclSpec.h"
> +#include "clang/Sema/LoopHint.h"
>  #include "clang/Sema/PrettyDeclStackTrace.h"
>  #include "clang/Sema/Scope.h"
>  #include "clang/Sema/TypoCorrection.h"
> @@ -357,6 +359,10 @@
>      ProhibitAttributes(Attrs);
>      HandlePragmaMSPragma();
>      return StmtEmpty();
> +
> +  case tok::annot_pragma_loop_hint:
> +    ProhibitAttributes(Attrs);
> +    return ParsePragmaLoopHint(Stmts, OnlyStatement, TrailingElseLoc, Attrs);
>    }
>
>    // If we reached this code, the statement must end in a semicolon.
> @@ -1759,6 +1765,37 @@
>    return Actions.ActOnReturnStmt(ReturnLoc, R.get(), getCurScope());
>  }
>
> +StmtResult Parser::ParsePragmaLoopHint(StmtVector &Stmts, bool OnlyStatement,
> +                                       SourceLocation *TrailingElseLoc,
> +                                       ParsedAttributesWithRange &Attrs) {
> +  // Create temporary attribute list.
> +  ParsedAttributesWithRange TempAttrs(AttrFactory);
> +
> +  // Get vectorize hints and consume annotated token.
> +  while (Tok.is(tok::annot_pragma_loop_hint)) {
> +    LoopHint Hint = HandlePragmaLoopHint();
> +    ConsumeToken();
> +
> +    if (!Hint.LoopLoc || !Hint.OptionLoc || !Hint.ValueLoc)
> +      continue;
> +
> +    ArgsUnion ArgHints[] = {Hint.OptionLoc, Hint.ValueLoc,
> +                            ArgsUnion(Hint.ValueExpr)};
> +    // FIXME: Replace AS_Keyword with Pragma spelling AS_Pragma.
> +    TempAttrs.addNew(Hint.LoopLoc->Ident, Hint.Range, 0, Hint.LoopLoc->Loc,
> +                     ArgHints, 3, AttributeList::AS_Keyword);
> +  }
> +
> +  // Get the next statement.
> +  MaybeParseCXX11Attributes(Attrs);
> +
> +  StmtResult S = ParseStatementOrDeclarationAfterAttributes(
> +      Stmts, OnlyStatement, TrailingElseLoc, Attrs);
> +
> +  Attrs.takeAllFrom(TempAttrs);
> +  return S;
> +}
> +
>  namespace {
>    class ClangAsmParserCallback : public llvm::MCAsmParserSemaCallback {
>      Parser &TheParser;
> Index: lib/Sema/SemaStmtAttr.cpp
> ===================================================================
> --- lib/Sema/SemaStmtAttr.cpp (revision 210052)
> +++ lib/Sema/SemaStmtAttr.cpp (working copy)
> @@ -16,6 +16,7 @@
>  #include "clang/Basic/SourceManager.h"
>  #include "clang/Sema/DelayedDiagnostic.h"
>  #include "clang/Sema/Lookup.h"
> +#include "clang/Sema/LoopHint.h"
>  #include "clang/Sema/ScopeInfo.h"
>  #include "llvm/ADT/StringExtras.h"
>
> @@ -42,7 +43,161 @@
>                                             A.getAttributeSpellingListIndex());
>  }
>
> +static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
> +                                SourceRange) {
> +  if (St->getStmtClass() != Stmt::DoStmtClass &&
> +      St->getStmtClass() != Stmt::ForStmtClass &&
> +      St->getStmtClass() != Stmt::CXXForRangeStmtClass &&
> +      St->getStmtClass() != Stmt::WhileStmtClass) {
> +    S.Diag(St->getLocStart(), diag::err_pragma_loop_precedes_nonloop);
> +    return nullptr;
> +  }
>
> +  IdentifierLoc *OptionLoc = A.getArgAsIdent(0);
> +  IdentifierInfo *OptionInfo = OptionLoc->Ident;
> +  IdentifierLoc *ValueLoc = A.getArgAsIdent(1);
> +  IdentifierInfo *ValueInfo = ValueLoc->Ident;
> +  Expr *ValueExpr = A.getArgAsExpr(2);
> +
> +  assert(OptionInfo && "Attribute must have valid option info.");
> +
> +  LoopHintAttr::OptionType Option = LoopHintAttr::Vectorize;
> +  if (OptionInfo->isStr("vectorize"))
> +    Option = LoopHintAttr::Vectorize;
> +  else if (OptionInfo->isStr("vectorize_width"))
> +    Option = LoopHintAttr::VectorizeWidth;
> +  else if (OptionInfo->isStr("interleave"))
> +    Option = LoopHintAttr::Interleave;
> +  else if (OptionInfo->isStr("interleave_count"))
> +    Option = LoopHintAttr::InterleaveCount;

This looks like it could use a StringSwitch and be a bit more clear.
Not horribly important.

> +
> +  int ValueInt;
> +  if (Option == LoopHintAttr::Vectorize || Option == LoopHintAttr::Interleave) {
> +    if (!ValueInfo) {
> +      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword)
> +          << /*MissingKeyword=*/true << "";
> +      return nullptr;
> +    }
> +
> +    if (ValueInfo->isStr("disable"))
> +      ValueInt = 0;
> +    else if (ValueInfo->isStr("enable"))
> +      ValueInt = 1;
> +    else {
> +      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword)
> +          << /*MissingKeyword=*/false << ValueInfo;
> +      return nullptr;
> +    }
> +  }
> +
> +  // FIXME: We should support template parameters for the loop hint value.
> +  // See bug report #19610.
> +  else if (Option == LoopHintAttr::VectorizeWidth ||
> +           Option == LoopHintAttr::InterleaveCount) {

The large amount of spacing between the closing curly brace and the
else if is a bit weird. I think the comment should go inside of the
else if, and the statement can move up to the closing curly brace of
the if statement, for clarity.

> +    llvm::APSInt ValueAPS;
> +    if (!ValueExpr || !ValueExpr->isIntegerConstantExpr(ValueAPS, S.Context)) {
> +      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_value)
> +          << /*MissingValue=*/true << "";
> +      return nullptr;
> +    }
> +
> +    if ((ValueInt = ValueAPS.getSExtValue()) < 1) {
> +      S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_value)
> +          << /*MissingValue=*/false << ValueInt;
> +      return nullptr;
> +    }
> +  }
> +
> +  return LoopHintAttr::CreateImplicit(S.Context, Option, ValueInt,
> +                                      A.getRange());
> +}
> +
> +static void
> +CheckForIncompatibleAttributes(Sema &S, SmallVectorImpl<const Attr *> &Attrs) {
> +  int PrevOptionValue[4] = {-1, -1, -1, -1};
> +  int OptionId[4] = {LoopHintAttr::Vectorize, LoopHintAttr::VectorizeWidth,
> +                     LoopHintAttr::Interleave, LoopHintAttr::InterleaveCount};
> +
> +  for (auto I = Attrs.begin(), E = Attrs.end(); I != E; ++I) {

Range-based for loop (using const auto *)?

> +    const LoopHintAttr *LH = dyn_cast<LoopHintAttr>(*I);
> +
> +    // Skip non loop hint attributes
> +    if (!LH)
> +      continue;
> +
> +    int State, Value;
> +    int Option = LH->getOption();
> +    int ValueInt = LH->getValue();
> +
> +    switch (Option) {
> +    case LoopHintAttr::Vectorize:
> +    case LoopHintAttr::VectorizeWidth:
> +      State = 0;
> +      Value = 1;
> +      break;
> +    case LoopHintAttr::Interleave:
> +    case LoopHintAttr::InterleaveCount:
> +      State = 2;
> +      Value = 3;
> +      break;
> +    }
> +
> +    SourceLocation ValueLoc = LH->getRange().getEnd();
> +
> +    // Compatibility testing is split into two cases.
> +    // 1. if the current loop hint sets state (enable/disable) - check against
> +    // previous state and value.
> +    // 2. if the current loop hint sets a value - check against previous state
> +    // and value.
> +
> +    if (Option == State) {
> +      if (PrevOptionValue[State] != -1) {
> +        // Cannot specify state twice.
> +        int PrevValue = PrevOptionValue[State];
> +        S.Diag(ValueLoc, diag::err_pragma_loop_compatibility)
> +            << /*Duplicate=*/true << LoopHintAttr::getOptionName(Option)
> +            << LoopHintAttr::getValueName(PrevValue)
> +            << LoopHintAttr::getOptionName(Option)
> +            << LoopHintAttr::getValueName(Value);
> +      }
> +
> +      if (PrevOptionValue[Value] != -1) {
> +        // Compare state with previous width/count.
> +        int PrevOption = OptionId[Value];
> +        int PrevValueInt = PrevOptionValue[Value];
> +        if ((ValueInt == 0 && PrevValueInt > 1) ||
> +            (ValueInt == 1 && PrevValueInt <= 1))
> +          S.Diag(ValueLoc, diag::err_pragma_loop_compatibility)
> +              << /*Duplicate=*/false << LoopHintAttr::getOptionName(PrevOption)
> +              << PrevValueInt << LoopHintAttr::getOptionName(Option)
> +              << LoopHintAttr::getValueName(ValueInt);
> +      }
> +    } else {
> +      if (PrevOptionValue[State] != -1) {
> +        // Compare width/count value with previous state.
> +        int PrevOption = OptionId[State];
> +        int PrevValueInt = PrevOptionValue[State];
> +        if ((ValueInt > 1 && PrevValueInt == 0) ||
> +            (ValueInt <= 1 && PrevValueInt == 1))
> +          S.Diag(ValueLoc, diag::err_pragma_loop_compatibility)
> +              << /*Duplicate=*/false << LoopHintAttr::getOptionName(PrevOption)
> +              << LoopHintAttr::getValueName(PrevValueInt)
> +              << LoopHintAttr::getOptionName(Option) << ValueInt;
> +      }
> +
> +      if (PrevOptionValue[Value] != -1) {
> +        // Cannot specify a width/count twice.
> +        int PrevValueInt = PrevOptionValue[Value];
> +        S.Diag(ValueLoc, diag::err_pragma_loop_compatibility)
> +            << /*Duplicate=*/true << LoopHintAttr::getOptionName(Option)
> +            << PrevValueInt << LoopHintAttr::getOptionName(Option) << ValueInt;
> +      }
> +    }
> +
> +    PrevOptionValue[Option] = ValueInt;
> +  }
> +}
> +
>  static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const AttributeList &A,
>                                    SourceRange Range) {
>    switch (A.getKind()) {
> @@ -53,6 +208,8 @@
>      return nullptr;
>    case AttributeList::AT_FallThrough:
>      return handleFallThroughAttr(S, St, A, Range);
> +  case AttributeList::AT_LoopHint:
> +    return handleLoopHintAttr(S, St, A, Range);
>    default:
>      // if we're here, then we parsed a known attribute, but didn't recognize
>      // it as a statement attribute => it is declaration attribute
> @@ -70,6 +227,8 @@
>        Attrs.push_back(a);
>    }
>
> +  CheckForIncompatibleAttributes(*this, Attrs);
> +
>    if (Attrs.empty())
>      return S;
>
> Index: test/CodeGen/pragma-loop.cpp
> ===================================================================
> --- test/CodeGen/pragma-loop.cpp (revision 0)
> +++ test/CodeGen/pragma-loop.cpp (working copy)
> @@ -0,0 +1,120 @@
> +// RUN: %clang_cc1 -std=c++11 -emit-llvm -o - %s | FileCheck %s

This test needs a target triple because of the mangling used (it fails
for me currently on Windows with an MSVC build).

> +
> +// Verify while loop is recognized after sequence of pragma clang loop directives.
> +void while_test(int *List, int Length) {
> +  // CHECK: define {{.*}} @_Z10while_test
> +  int i = 0;
> +
> +#pragma clang loop vectorize(enable)
> +#pragma clang loop interleave_count(4)
> +#pragma clang loop vectorize_width(4)
> +  while (i < Length) {
> +    // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_1:.*]]
> +    List[i] = i * 2;
> +    i++;
> +  }
> +}
> +
> +// Verify do loop is recognized after multi-option pragma clang loop directive.
> +void do_test(int *List, int Length) {
> +  int i = 0;
> +
> +#pragma clang loop vectorize_width(8) interleave_count(4)
> +  do {
> +    // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_2:.*]]
> +    List[i] = i * 2;
> +    i++;
> +  } while (i < Length);
> +}
> +
> +// Verify for loop is recognized after sequence of pragma clang loop directives.
> +void for_test(int *List, int Length) {
> +#pragma clang loop interleave(enable)
> +#pragma clang loop interleave_count(4)
> +  for (int i = 0; i < Length; i++) {
> +    // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_3:.*]]
> +    List[i] = i * 2;
> +  }
> +}
> +
> +// Verify c++11 for range loop is recognized after
> +// sequence of pragma clang loop directives.
> +void for_range_test() {
> +  double List[100];
> +
> +#pragma clang loop vectorize_width(2) interleave_count(2)
> +  for (int i : List) {
> +    // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_4:.*]]
> +    List[i] = i;
> +  }
> +}
> +
> +// Verify disable pragma clang loop directive generates correct metadata
> +void disable_test(int *List, int Length) {
> +#pragma clang loop vectorize(disable)
> +  for (int i = 0; i < Length; i++) {
> +    // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_5:.*]]
> +    List[i] = i * 2;
> +  }
> +}
> +
> +#define VECWIDTH 2
> +#define INTCOUNT 2
> +
> +// Verify defines are correctly resolved in pragma clang loop directive
> +void for_define_test(int *List, int Length, int Value) {
> +#pragma clang loop vectorize_width(VECWIDTH) interleave_count(INTCOUNT)
> +  for (int i = 0; i < Length; i++) {
> +    // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_6:.*]]
> +    List[i] = i * Value;
> +  }
> +}
> +
> +// Verify metadata is generated when template is used.
> +template <typename A>
> +void for_template_test(A *List, int Length, A Value) {
> +
> +#pragma clang loop vectorize_width(8) interleave_count(8)
> +  for (int i = 0; i < Length; i++) {
> +    // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_7:.*]]
> +    List[i] = i * Value;
> +  }
> +}
> +
> +// Verify define is resolved correctly when template is used.
> +template <typename A>
> +void for_template_define_test(A *List, int Length, A Value) {
> +#pragma clang loop vectorize_width(VECWIDTH) interleave_count(INTCOUNT)
> +  for (int i = 0; i < Length; i++) {
> +    // CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_8:.*]]
> +    List[i] = i * Value;
> +  }
> +}
> +
> +#undef VECWIDTH
> +#undef INTCOUNT
> +
> +// Use templates defined above. Test verifies metadata is generated correctly.
> +void template_test(double *List, int Length) {
> +  double Value = 10;
> +
> +  for_template_test<double>(List, Length, Value);
> +  for_template_define_test<double>(List, Length, Value);
> +}
> +
> +// CHECK: ![[LOOP_1]] = metadata !{metadata ![[LOOP_1]], metadata ![[WIDTH_4:.*]], metadata ![[UNROLL_4:.*]], metadata ![[ENABLE_1:.*]]}
> +// CHECK: ![[WIDTH_4]] = metadata !{metadata !"llvm.vectorizer.width", i32 4}
> +// CHECK: ![[UNROLL_4]] = metadata !{metadata !"llvm.vectorizer.unroll", i32 4}
> +// CHECK: ![[ENABLE_1]] = metadata !{metadata !"llvm.vectorizer.enable", i1 true}
> +// CHECK: ![[LOOP_2]] = metadata !{metadata ![[LOOP_2:.*]], metadata ![[UNROLL_4:.*]], metadata ![[WIDTH_8:.*]]}
> +// CHECK: ![[WIDTH_8]] = metadata !{metadata !"llvm.vectorizer.width", i32 8}
> +// CHECK: ![[LOOP_3]] = metadata !{metadata ![[LOOP_3]], metadata ![[UNROLL_4:.*]], metadata ![[ENABLE_1:.*]]}
> +// CHECK: ![[LOOP_4]] = metadata !{metadata ![[LOOP_4]], metadata ![[UNROLL_2:.*]], metadata ![[WIDTH_2:.*]]}
> +// CHECK: ![[UNROLL_2]] = metadata !{metadata !"llvm.vectorizer.unroll", i32 2}
> +// CHECK: ![[WIDTH_2]] = metadata !{metadata !"llvm.vectorizer.width", i32 2}
> +// CHECK: ![[LOOP_5]] = metadata !{metadata ![[LOOP_5]], metadata ![[WIDTH_1:.*]]}
> +// CHECK: ![[WIDTH_1]] = metadata !{metadata !"llvm.vectorizer.width", i32 1}
> +// CHECK: ![[LOOP_6]] = metadata !{metadata ![[LOOP_6]], metadata ![[UNROLL_2:.*]], metadata ![[WIDTH_2:.*]]}
> +// CHECK: ![[LOOP_7]] = metadata !{metadata ![[LOOP_7]], metadata ![[UNROLL_8:.*]], metadata ![[WIDTH_8:.*]]}
> +// CHECK: ![[UNROLL_8]] = metadata !{metadata !"llvm.vectorizer.unroll", i32 8}
> +// CHECK: ![[LOOP_8]] = metadata !{metadata ![[LOOP_8]], metadata ![[UNROLL_2:.*]], metadata ![[WIDTH_2:.*]]}
> Index: test/PCH/pragma-loop.cpp
> ===================================================================
> --- test/PCH/pragma-loop.cpp (revision 0)
> +++ test/PCH/pragma-loop.cpp (working copy)
> @@ -0,0 +1,62 @@
> +// RUN: %clang_cc1 -emit-pch -o %t.a %s
> +// RUN: %clang_cc1 -include-pch %t.a %s -ast-print -o - | FileCheck %s
> +
> +// FIXME: A bug in ParsedAttributes causes the order of the attributes to be
> +// reversed. The checks are consequently in the reverse order below.
> +
> +// CHECK: #pragma clang loop interleave_count(8)
> +// CHECK: #pragma clang loop vectorize_width(4)
> +// CHECK: #pragma clang loop interleave(disable)
> +// CHECK: #pragma clang loop vectorize(enable)
> +// CHECK: #pragma clang loop interleave(enable)
> +// CHECK: #pragma clang loop vectorize(disable)
> +
> +#ifndef HEADER
> +#define HEADER
> +
> +class pragma_test {
> +public:
> +  inline void run1(int *List, int Length) {
> +    int i = 0;
> +#pragma clang loop vectorize_width(4)
> +#pragma clang loop interleave_count(8)
> +    while (i < Length) {
> +      List[i] = i;
> +      i++;
> +    }
> +  }
> +
> +  inline void run2(int *List, int Length) {
> +    int i = 0;
> +#pragma clang loop vectorize(enable)
> +#pragma clang loop interleave(disable)
> +    while (i - 1 < Length) {
> +      List[i] = i;
> +      i++;
> +    }
> +  }
> +
> +  inline void run3(int *List, int Length) {
> +    int i = 0;
> +#pragma clang loop vectorize(disable)
> +#pragma clang loop interleave(enable)
> +    while (i - 3 < Length) {
> +      List[i] = i;
> +      i++;
> +    }
> +  }
> +};
> +
> +#else
> +
> +void test() {
> +  int List[100];
> +
> +  pragma_test pt;
> +
> +  pt.run1(List, 100);
> +  pt.run2(List, 100);
> +  pt.run3(List, 100);
> +}
> +
> +#endif
> Index: test/Parser/pragma-loop-ast.cpp
> ===================================================================
> --- test/Parser/pragma-loop-ast.cpp (revision 0)
> +++ test/Parser/pragma-loop-ast.cpp (working copy)
> @@ -0,0 +1,35 @@
> +// RUN: %clang_cc1 -ast-print %s | FileCheck %s
> +
> +// FIXME: A bug in ParsedAttributes causes the order of the attributes to be
> +// reversed. The checks are consequently in the reverse order below.
> +
> +// CHECK: #pragma clang loop interleave_count(8)
> +// CHECK: #pragma clang loop vectorize_width(4)
> +// CHECK: #pragma clang loop interleave(disable)
> +// CHECK: #pragma clang loop vectorize(enable)
> +// CHECK: #pragma clang loop interleave(enable)
> +// CHECK: #pragma clang loop vectorize(disable)
> +
> +void test(int *List, int Length) {
> +  int i = 0;
> +#pragma clang loop vectorize_width(4)
> +#pragma clang loop interleave_count(8)
> +  while (i < Length) {
> +    List[i] = i * 2;
> +    i++;
> +  }
> +
> +#pragma clang loop vectorize(enable)
> +#pragma clang loop interleave(disable)
> +  while (i - 1 < Length) {
> +    List[i] = i * 2;
> +    i++;
> +  }
> +
> +#pragma clang loop vectorize(disable)
> +#pragma clang loop interleave(enable)
> +  while (i - 2 < Length) {
> +    List[i] = i * 2;
> +    i++;
> +  }
> +}
> Index: test/Parser/pragma-loop.cpp
> ===================================================================
> --- test/Parser/pragma-loop.cpp (revision 0)
> +++ test/Parser/pragma-loop.cpp (working copy)
> @@ -0,0 +1,132 @@
> +// RUN: %clang_cc1 -std=c++11 -verify %s
> +
> +// Note that this puts the expected lines before the directives to work around
> +// limitations in the -verify mode.
> +
> +void test(int *List, int Length) {
> +  int i = 0;
> +
> +#pragma clang loop vectorize(enable)
> +#pragma clang loop interleave(enable)
> +  while (i + 1 < Length) {
> +    List[i] = i;
> +  }
> +
> +#pragma clang loop vectorize_width(4)
> +#pragma clang loop interleave_count(8)
> +  while (i < Length) {
> +    List[i] = i;
> +  }
> +
> +#pragma clang loop vectorize(disable)
> +#pragma clang loop interleave(disable)
> +  while (i - 1 < Length) {
> +    List[i] = i;
> +  }
> +
> +#pragma clang loop vectorize_width(4) interleave_count(8)
> +  while (i - 2 < Length) {
> +    List[i] = i;
> +  }
> +
> +#pragma clang loop interleave_count(16)
> +  while (i - 3 < Length) {
> +    List[i] = i;
> +  }
> +
> +  int VList[Length];
> +#pragma clang loop vectorize(disable) interleave(disable)
> +  for (int j : VList) {
> +    VList[j] = List[j];
> +  }
> +
> +/* expected-error {{expected '('}} */ #pragma clang loop vectorize
> +/* expected-error {{expected '('}} */ #pragma clang loop interleave
> +
> +/* expected-error {{expected ')'}} */ #pragma clang loop vectorize(enable
> +/* expected-error {{expected ')'}} */ #pragma clang loop interleave(enable
> +
> +/* expected-error {{expected ')'}} */ #pragma clang loop vectorize_width(4
> +/* expected-error {{expected ')'}} */ #pragma clang loop interleave_count(4
> +
> +/* expected-error {{missing option}} */ #pragma clang loop
> +/* expected-error {{invalid option 'badkeyword'}} */ #pragma clang loop badkeyword
> +/* expected-error {{invalid option 'badkeyword'}} */ #pragma clang loop badkeyword(enable)
> +/* expected-error {{invalid option 'badkeyword'}} */ #pragma clang loop vectorize(enable) badkeyword(4)
> +/* expected-warning {{extra tokens at end of '#pragma clang loop'}} */ #pragma clang loop vectorize(enable) ,
> +
> +  while (i-4 < Length) {
> +    List[i] = i;
> +  }
> +
> +/* expected-error {{invalid value 0; expected a positive integer value}} */ #pragma clang loop vectorize_width(0)
> +/* expected-error {{invalid value 0; expected a positive integer value}} */ #pragma clang loop interleave_count(0)
> +  while (i-5 < Length) {
> +    List[i] = i;
> +  }
> +
> +/* expected-error {{invalid value -1294967296; expected a positive integer value}} */ #pragma clang loop vectorize_width(3000000000)
> +/* expected-error {{invalid value -1294967296; expected a positive integer value}} */ #pragma clang loop interleave_count(3000000000)
> +  while (i-6 < Length) {
> +    List[i] = i;
> +  }
> +
> +/* expected-error {{missing value; expected a positive integer value}} */ #pragma clang loop vectorize_width(badvalue)
> +/* expected-error {{missing value; expected a positive integer value}} */ #pragma clang loop interleave_count(badvalue)
> +  while (i-6 < Length) {
> +    List[i] = i;
> +  }
> +
> +/* expected-error {{invalid keyword 'badidentifier'; expected 'enable' or 'disable'}} */ #pragma clang loop vectorize(badidentifier)
> +/* expected-error {{invalid keyword 'badidentifier'; expected 'enable' or 'disable'}} */ #pragma clang loop interleave(badidentifier)
> +  while (i-7 < Length) {
> +    List[i] = i;
> +  }
> +
> +#pragma clang loop vectorize(enable)
> +/* expected-error {{expected a for, while, or do-while loop to follow the '#pragma clang loop' directive}} */ int j = Length;
> +  List[0] = List[1];
> +
> +  while (j-1 < Length) {
> +    List[j] = j;
> +  }
> +
> +// FIXME: A bug in ParsedAttributes causes the order of the attributes to be
> +// processed in reverse. Consequently, the errors occur on the first of pragma
> +// of the next three tests rather than the last, and the order of the kinds
> +// is also reversed.
> +
> +/* expected-error {{incompatible directives 'vectorize(disable)' and 'vectorize_width(4)'}} */ #pragma clang loop vectorize_width(4)
> +#pragma clang loop vectorize(disable)
> +/* expected-error {{incompatible directives 'interleave(disable)' and 'interleave_count(4)'}} */ #pragma clang loop interleave_count(4)
> +#pragma clang loop interleave(disable)
> +  while (i-8 < Length) {
> +    List[i] = i;
> +  }
> +
> +/* expected-error {{duplicate directives 'vectorize(disable)' and 'vectorize(enable)'}} */ #pragma clang loop vectorize(enable)
> +#pragma clang loop vectorize(disable)
> +/* expected-error {{duplicate directives 'interleave(disable)' and 'interleave(enable)'}} */ #pragma clang loop interleave(enable)
> +#pragma clang loop interleave(disable)
> +  while (i-9 < Length) {
> +    List[i] = i;
> +  }
> +
> +/* expected-error {{incompatible directives 'vectorize_width(4)' and 'vectorize(disable)'}} */ #pragma clang loop vectorize(disable)
> +#pragma clang loop vectorize_width(4)
> +/* expected-error {{incompatible directives 'interleave_count(4)' and 'interleave(disable)'}} */ #pragma clang loop interleave(disable)
> +#pragma clang loop interleave_count(4)
> +  while (i-10 < Length) {
> +    List[i] = i;
> +  }
> +
> +/* expected-error {{duplicate directives 'vectorize_width(4)' and 'vectorize_width(8)'}} */ #pragma clang loop vectorize_width(8)
> +#pragma clang loop vectorize_width(4)
> +/* expected-error {{duplicate directives 'interleave_count(4)' and 'interleave_count(8)'}} */ #pragma clang loop interleave_count(8)
> +#pragma clang loop interleave_count(4)
> +  while (i-11 < Length) {
> +    List[i] = i;
> +  }
> +
> +#pragma clang loop interleave(enable)
> +/* expected-error {{expected statement}} */ }
>

~Aaron

On Mon, Jun 2, 2014 at 7:18 PM, Tyler Nowicki <tnowicki at apple.com> wrote:
> Hi Richard,
>
> Thanks again for the review. I’m glad to hear its getting closer. I’ve applied your suggestions. Here is the updated patch.
>
>> Once you move to supporting arbitrary constant expressions as the argument, I think you may want to split this into two separate Attrs (one for vectorize and interleave, that have a BoolArgument, and one for vectorize_width and interleave_count, that have an ExprArgument).
>>
>> I also think we should have different spellings for these different enum values, once we have proper pragma spelling support:
>>
>>   let Spellings = [Pragma<"clang", "loop", "vectorize_width">,
>>                    Pragma<"clang", "loop", "interleave_count">];
>>   let Args = [ExprArgument<"Value">];
>>
>> ... but that can all be deferred for a later patch.
>
> I like the idea of separating the LoopHintAttrs that may make it easier to support c++11 spellings as well.
>
> Tyler
>




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