3 files changed, 37 insertions, 6 deletions

diff --git a/clang/lib/CodeGen/CGLoopInfo.cpp b/clang/lib/CodeGen/CGLoopInfo.cpp
index 0675544bedf..3254fb81dcc 100644
--- a/clang/lib/CodeGen/CGLoopInfo.cpp
+++ b/clang/lib/CodeGen/CGLoopInfo.cpp
@@ -8,6 +8,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "CGLoopInfo.h"
+#include "clang/AST/Attr.h"
+#include "clang/Sema/LoopHint.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/InstrTypes.h"
@@ -76,7 +78,33 @@ LoopInfo::LoopInfo(BasicBlock *Header, const LoopAttributes &Attrs)
   LoopID = createMetadata(Header->getContext(), Attrs);
 }
 
-void LoopInfoStack::push(BasicBlock *Header) {
+void LoopInfoStack::push(BasicBlock *Header, ArrayRef<const Attr *> Attrs) {
+  for (const auto *Attr : Attrs) {
+    const LoopHintAttr *LH = dyn_cast<LoopHintAttr>(Attr);
+
+    // Skip non loop hint attributes
+    if (!LH)
+      continue;
+
+    LoopHintAttr::OptionType Option = LH->getOption();
+    LoopHintAttr::LoopHintState State = LH->getState();
+    switch (Option) {
+    case LoopHintAttr::Vectorize:
+    case LoopHintAttr::Interleave:
+      if (State == LoopHintAttr::AssumeSafety) {
+        // Apply "llvm.mem.parallel_loop_access" metadata to load/stores.
+        setParallel(true);
+      }
+      break;
+    case LoopHintAttr::VectorizeWidth:
+    case LoopHintAttr::InterleaveCount:
+    case LoopHintAttr::Unroll:
+    case LoopHintAttr::UnrollCount:
+      // Nothing to do here for these loop hints.
+      break;
+    }
+  }
+
   Active.push_back(LoopInfo(Header, StagedAttrs));
   // Clear the attributes so nested loops do not inherit them.
   StagedAttrs.clear();
diff --git a/clang/lib/CodeGen/CGLoopInfo.h b/clang/lib/CodeGen/CGLoopInfo.h
index aee162118a2..2249937cd0d 100644
--- a/clang/lib/CodeGen/CGLoopInfo.h
+++ b/clang/lib/CodeGen/CGLoopInfo.h
@@ -15,6 +15,7 @@
 #ifndef LLVM_CLANG_LIB_CODEGEN_CGLOOPINFO_H
 #define LLVM_CLANG_LIB_CODEGEN_CGLOOPINFO_H
 
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/IR/Value.h"
@@ -27,6 +28,7 @@ class MDNode;
 } // end namespace llvm
 
 namespace clang {
+class Attr;
 namespace CodeGen {
 
 /// \brief Attributes that may be specified on loops.
@@ -86,7 +88,8 @@ public:
 
   /// \brief Begin a new structured loop. The set of staged attributes will be
   /// applied to the loop and then cleared.
-  void push(llvm::BasicBlock *Header);
+  void push(llvm::BasicBlock *Header,
+            llvm::ArrayRef<const Attr *> Attrs = llvm::None);
 
   /// \brief End the current loop.
   void pop();
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 744c61384c8..57f55aacfa6 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -682,7 +682,7 @@ void CodeGenFunction::EmitWhileStmt(const WhileStmt &S,
   JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond");
   EmitBlock(LoopHeader.getBlock());
 
-  LoopStack.push(LoopHeader.getBlock());
+  LoopStack.push(LoopHeader.getBlock(), WhileAttrs);
 
   // Create an exit block for when the condition fails, which will
   // also become the break target.
@@ -776,7 +776,7 @@ void CodeGenFunction::EmitDoStmt(const DoStmt &S,
   // Emit the body of the loop.
   llvm::BasicBlock *LoopBody = createBasicBlock("do.body");
 
-  LoopStack.push(LoopBody);
+  LoopStack.push(LoopBody, DoAttrs);
 
   EmitBlockWithFallThrough(LoopBody, &S);
   {
@@ -842,7 +842,7 @@ void CodeGenFunction::EmitForStmt(const ForStmt &S,
   llvm::BasicBlock *CondBlock = Continue.getBlock();
   EmitBlock(CondBlock);
 
-  LoopStack.push(CondBlock);
+  LoopStack.push(CondBlock, ForAttrs);
 
   // If the for loop doesn't have an increment we can just use the
   // condition as the continue block.  Otherwise we'll need to create
@@ -940,7 +940,7 @@ CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S,
   llvm::BasicBlock *CondBlock = createBasicBlock("for.cond");
   EmitBlock(CondBlock);
 
-  LoopStack.push(CondBlock);
+  LoopStack.push(CondBlock, ForAttrs);
 
   // If there are any cleanups between here and the loop-exit scope,
   // create a block to stage a loop exit along.