From c09611c5443fcc91fcc7452175017e2402c116c8 Mon Sep 17 00:00:00 2001
From: Michal Babej <michal.babej@tuni.fi>
Date: Fri, 8 Mar 2019 10:02:56 +0200
Subject: [PATCH] Fix #663: update the parallel loop metadata for LLVM 8.0
 format

---
 lib/llvmopencl/ParallelRegion.cc | 20 +++++++++++++-------
 lib/llvmopencl/ParallelRegion.h  |  2 +-
 lib/llvmopencl/WorkitemLoops.cc  | 21 +++++++++++++++------
 3 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/lib/llvmopencl/ParallelRegion.cc b/lib/llvmopencl/ParallelRegion.cc
index 067c61d21e..b2d1fee306 100644
--- a/lib/llvmopencl/ParallelRegion.cc
+++ b/lib/llvmopencl/ParallelRegion.cc
@@ -471,20 +471,26 @@ ParallelRegion::Verify()
  * !1 { metadata !1 }
  * !2 { metadata !2 }
  */
-void
-ParallelRegion::AddParallelLoopMetadata(llvm::MDNode *identifier) {
 
+#ifdef LLVM_OLDER_THAN_8_0
+#define PARALLEL_MD_NAME "llvm.mem.parallel_loop_access"
+#else
+#define PARALLEL_MD_NAME "llvm.access.group"
+#endif
+
+void ParallelRegion::AddParallelLoopMetadata(llvm::MDNode *Identifier) {
   for (iterator i = begin(), e = end(); i != e; ++i) {
     BasicBlock* bb = *i;      
     for (BasicBlock::iterator ii = bb->begin(), ee = bb->end();
          ii != ee; ii++) {
+
       if (ii->mayReadOrWriteMemory()) {
-        MDNode *newMD = MDNode::get(bb->getContext(), identifier);
-        MDNode *oldMD = ii->getMetadata("llvm.mem.parallel_loop_access");
-        if (oldMD != NULL) {
-          newMD = llvm::MDNode::concatenate(oldMD, newMD);
+        MDNode *NewMD = MDNode::get(bb->getContext(), Identifier);
+        MDNode *OldMD = ii->getMetadata(PARALLEL_MD_NAME);
+        if (OldMD != nullptr) {
+          NewMD = llvm::MDNode::concatenate(OldMD, NewMD);
         }
-        ii->setMetadata("llvm.mem.parallel_loop_access", newMD);
+        ii->setMetadata(PARALLEL_MD_NAME, NewMD);
       }
     }
   }
diff --git a/lib/llvmopencl/ParallelRegion.h b/lib/llvmopencl/ParallelRegion.h
index f9bdae4a68..e3af931991 100644
--- a/lib/llvmopencl/ParallelRegion.h
+++ b/lib/llvmopencl/ParallelRegion.h
@@ -79,7 +79,7 @@ class Kernel;
                        std::size_t y = 0, 
                        std::size_t z = 0);
 
-    void AddParallelLoopMetadata(llvm::MDNode *identifier);
+    void AddParallelLoopMetadata(llvm::MDNode *Identifier);
 
     bool HasBlock(llvm::BasicBlock *bb);
 
diff --git a/lib/llvmopencl/WorkitemLoops.cc b/lib/llvmopencl/WorkitemLoops.cc
index abcc3a8bf9..dd27305447 100644
--- a/lib/llvmopencl/WorkitemLoops.cc
+++ b/lib/llvmopencl/WorkitemLoops.cc
@@ -34,6 +34,7 @@
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/MDBuilder.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Module.h"
@@ -298,13 +299,18 @@ WorkitemLoops::CreateLoopAround
 
   /* This creation of the identifier metadata is copied from
      LLVM's MDBuilder::createAnonymousTBAARoot(). */
-#ifdef LLVM_OLDER_THAN_3_7
-  MDNode *Dummy = MDNode::getTemporary(C, ArrayRef<Metadata*>());
-#else
+
   MDNode *Dummy = MDNode::getTemporary(C, ArrayRef<Metadata*>()).release();
+#ifdef LLVM_OLDER_THAN_8_0
+  MDNode *Root = MDNode::get(C, Dummy);
+#else
+  MDNode *AccessGroupMD = MDNode::getDistinct(C, {});
+  MDNode *ParallelAccessMD = MDNode::get(
+      C, {MDString::get(C, "llvm.loop.parallel_accesses"), AccessGroupMD});
+
+  MDNode *Root = MDNode::get(C, {Dummy, ParallelAccessMD});
 #endif
 
-  MDNode *Root = MDNode::get(C, Dummy);
   // At this point we have
   //   !0 = metadata !{}            <- dummy
   //   !1 = metadata !{metadata !0} <- root
@@ -313,10 +319,13 @@ WorkitemLoops::CreateLoopAround
   MDNode::deleteTemporary(Dummy);
   // We now have
   //   !1 = metadata !{metadata !1} <- self-referential root
-
   loopBranch->setMetadata("llvm.loop", Root);
-  region.AddParallelLoopMetadata(Root);
 
+#ifdef LLVM_OLDER_THAN_8_0
+  region.AddParallelLoopMetadata(Root);
+#else
+  region.AddParallelLoopMetadata(AccessGroupMD);
+#endif
 
   builder.SetInsertPoint(loopEndBB);
   builder.CreateBr(oldExit);