1 files changed, 10 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
index c2a737d8f9a4..c7d71eb5633e 100644
--- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -1437,9 +1437,18 @@ bool JumpThreadingPass::simplifyPartiallyRedundantLoad(LoadInst *LoadI) {
     // AvailablePreds vector as we go so that all of the PHI entries for this
     // predecessor use the same bitcast.
     Value *&PredV = I->second;
-    if (PredV->getType() != LoadI->getType())
+    if (PredV->getType() != LoadI->getType()) {
       PredV = CastInst::CreateBitOrPointerCast(
           PredV, LoadI->getType(), "", P->getTerminator()->getIterator());
+      // The new cast is producing the value used to replace the load
+      // instruction, so uses the load's debug location. If P does not always
+      // branch to the load BB however then the debug location must be dropped,
+      // as it is hoisted past a conditional branch.
+      DebugLoc DL = P->getTerminator()->getNumSuccessors() == 1
+                        ? LoadI->getDebugLoc()
+                        : DebugLoc::getDropped();
+      cast<CastInst>(PredV)->setDebugLoc(DL);
+    }
 
     PN->addIncoming(PredV, I->first);
   }