1 files changed, 34 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopRotation.cpp b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
index 214f41790f9..a27a314cac5 100644
--- a/llvm/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
@@ -111,6 +111,40 @@ static void RewriteUsesOfClonedInstructions(BasicBlock *OrigHeader,
       // Anything else can be handled by SSAUpdater.
       SSA.RewriteUse(U);
     }
+
+    // Replace MetadataAsValue(ValueAsMetadata(OrigHeaderVal)) uses in debug
+    // intrinsics.
+    LLVMContext &C = OrigHeader->getContext();
+    if (auto *VAM = ValueAsMetadata::getIfExists(OrigHeaderVal)) {
+      if (auto *MAV = MetadataAsValue::getIfExists(C, VAM)) {
+        for (auto UI = MAV->use_begin(), E = MAV->use_end(); UI != E; ) {
+          // Grab the use before incrementing the iterator. Otherwise, altering
+          // the Use will invalidate the iterator.
+          Use &U = *UI++;
+          DbgInfoIntrinsic *UserInst = dyn_cast<DbgInfoIntrinsic>(U.getUser());
+          if (!UserInst) continue;
+
+          // The original users in the OrigHeader are already using the original
+          // definitions.
+          BasicBlock *UserBB = UserInst->getParent();
+          if (UserBB == OrigHeader)
+            continue;
+
+          // Users in the OrigPreHeader need to use the value to which the
+          // original definitions are mapped and anything else can be handled by
+          // the SSAUpdater. To avoid adding PHINodes, check if the value is
+          // available in UserBB, if not substitute undef.
+          Value *NewVal;
+          if (UserBB == OrigPreheader)
+            NewVal = OrigPreHeaderVal;
+          else if (SSA.HasValueForBlock(UserBB))
+            NewVal = SSA.GetValueInMiddleOfBlock(UserBB);
+          else
+            NewVal = UndefValue::get(OrigHeaderVal->getType());
+          U = MetadataAsValue::get(C, ValueAsMetadata::get(NewVal));
+        }
+      }
+    }
   }
 }