Index: include/llvm/Transforms/Utils/UnrollLoop.h
===================================================================
--- include/llvm/Transforms/Utils/UnrollLoop.h
+++ include/llvm/Transforms/Utils/UnrollLoop.h
@@ -34,7 +34,7 @@
 bool UnrollRuntimeLoopProlog(Loop *L, unsigned Count, LoopInfo *LI,
                              LPPassManager* LPM);
 
-const MDNode *GetUnrollMetadata(const MDNode *LoopID, StringRef Name);
+MDNode *GetUnrollMetadata(MDNode *LoopID, StringRef Name);
 }
 
 #endif
Index: lib/Target/NVPTX/NVPTXAsmPrinter.cpp
===================================================================
--- lib/Target/NVPTX/NVPTXAsmPrinter.cpp
+++ lib/Target/NVPTX/NVPTXAsmPrinter.cpp
@@ -442,8 +442,7 @@
       continue;
     }
     if (const BasicBlock *PBB = PMBB->getBasicBlock()) {
-      if (const MDNode *LoopID =
-              PBB->getTerminator()->getMetadata("llvm.loop")) {
+      if (MDNode *LoopID = PBB->getTerminator()->getMetadata("llvm.loop")) {
         if (GetUnrollMetadata(LoopID, "llvm.loop.unroll.disable"))
           return true;
       }
Index: lib/Transforms/Scalar/LoopUnrollPass.cpp
===================================================================
--- lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -231,11 +231,10 @@
 // Returns the loop hint metadata node with the given name (for example,
 // "llvm.loop.unroll.count").  If no such metadata node exists, then nullptr is
 // returned.
-static const MDNode *GetUnrollMetadataForLoop(const Loop *L, StringRef Name) {
-  MDNode *LoopID = L->getLoopID();
-  if (!LoopID)
-    return nullptr;
-  return GetUnrollMetadata(LoopID, Name);
+static MDNode *GetUnrollMetadataForLoop(const Loop *L, StringRef Name) {
+  if (MDNode *LoopID = L->getLoopID())
+    return GetUnrollMetadata(LoopID, Name);
+  return nullptr;
 }
 
 // Returns true if the loop has an unroll(full) pragma.
@@ -251,7 +250,7 @@
 // If loop has an unroll_count pragma return the (necessarily
 // positive) value from the pragma.  Otherwise return 0.
 static unsigned UnrollCountPragmaValue(const Loop *L) {
-  const MDNode *MD = GetUnrollMetadataForLoop(L, "llvm.loop.unroll.count");
+  MDNode *MD = GetUnrollMetadataForLoop(L, "llvm.loop.unroll.count");
   if (MD) {
     assert(MD->getNumOperands() == 2 &&
            "Unroll count hint metadata should have two operands.");
Index: lib/Transforms/Utils/LoopUnroll.cpp
===================================================================
--- lib/Transforms/Utils/LoopUnroll.cpp
+++ lib/Transforms/Utils/LoopUnroll.cpp
@@ -553,16 +553,17 @@
 /// Given an llvm.loop loop id metadata node, returns the loop hint metadata
 /// node with the given name (for example, "llvm.loop.unroll.count"). If no
 /// such metadata node exists, then nullptr is returned.
-const MDNode *llvm::GetUnrollMetadata(const MDNode *LoopID, StringRef Name) {
+MDNode *llvm::GetUnrollMetadata(MDNode *LoopID, StringRef Name) {
   // First operand should refer to the loop id itself.
   assert(LoopID->getNumOperands() > 0 && "requires at least one operand");
+  assert(LoopID->getOperand(0) == LoopID && "invalid loop id");
 
   for (unsigned i = 1, e = LoopID->getNumOperands(); i < e; ++i) {
-    const MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i));
+    MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i));
     if (!MD)
       continue;
 
-    const MDString *S = dyn_cast<MDString>(MD->getOperand(0));
+    MDString *S = dyn_cast<MDString>(MD->getOperand(0));
     if (!S)
       continue;