1 files changed, 16 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp
index a1f8e7484bc..53d444b309d 100644
--- a/llvm/lib/Transforms/Utils/LCSSA.cpp
+++ b/llvm/lib/Transforms/Utils/LCSSA.cpp
@@ -41,6 +41,7 @@
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/PredIteratorCache.h"
 #include "llvm/Pass.h"
 #include "llvm/Transforms/Utils.h"
@@ -201,6 +202,21 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
       SSAUpdate.RewriteUse(*UseToRewrite);
     }
 
+    SmallVector<DbgValueInst *, 4> DbgValues;
+    llvm::findDbgValues(DbgValues, I);
+
+    // Update pre-existing debug value uses that reside outside the loop.
+    auto &Ctx = I->getContext();
+    for (auto DVI : DbgValues) {
+      BasicBlock *UserBB = DVI->getParent();
+      if (InstBB == UserBB || L->contains(UserBB))
+        continue;
+      // We currently only handle debug values residing in blocks where we have
+      // inserted a PHI instruction.
+      if (Value *V = SSAUpdate.FindValueForBlock(UserBB))
+        DVI->setOperand(0, MetadataAsValue::get(Ctx, ValueAsMetadata::get(V)));
+    }
+
     // SSAUpdater might have inserted phi-nodes inside other loops. We'll need
     // to post-process them to keep LCSSA form.
     for (PHINode *InsertedPN : InsertedPHIs) {