[Unroll][DebugInfo] Propagate loop body's debug location to epilog preheader

NewExit and epilog PreHeader should has the same debug loc as the original loop
body, instead of original loop exit.

llvm-svn: 321465

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index efff06f79cb..e00541d3c81 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -648,8 +648,13 @@ bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count,
     SmallVector<BasicBlock*, 4> Preds(predecessors(LatchExit));
     NewExit = SplitBlockPredecessors(LatchExit, Preds, ".unr-lcssa",
                                      DT, LI, PreserveLCSSA);
+    // NewExit gets its DebugLoc from LatchExit, which is not part of the
+    // original Loop.
+    // Fix this by setting Loop's DebugLoc to NewExit.
+    auto *NewExitTerminator = NewExit->getTerminator();
+    NewExitTerminator->setDebugLoc(Header->getTerminator()->getDebugLoc());
     // Split NewExit to insert epilog remainder loop.
-    EpilogPreHeader = SplitBlock(NewExit, NewExit->getTerminator(), DT, LI);
+    EpilogPreHeader = SplitBlock(NewExit, NewExitTerminator, DT, LI);
     EpilogPreHeader->setName(Header->getName() + ".epil.preheader");
   } else {
     // If prolog remainder