[LoopUnrolling] Fix a bug introduced in r259869 (PR26688).

The issue was that we only required LCSSA rebuilding if the immediate
parent-loop had values used outside of it. The fix is to enaable the
same logic for all outer loops, not only immediate parent.

llvm-svn: 261575

1 files changed, 6 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index 5c83cef573b..5152220e626 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -142,9 +142,13 @@ static bool needToInsertPhisForLCSSA(Loop *L, std::vector<BasicBlock *> Blocks,
       continue;
     for (Instruction &I : *BB) {
       for (Use &U : I.operands()) {
-        if (auto Def = dyn_cast<Instruction>(U))
-          if (LI->getLoopFor(Def->getParent()) == L)
+        if (auto Def = dyn_cast<Instruction>(U)) {
+          Loop *DefLoop = LI->getLoopFor(Def->getParent());
+          if (!DefLoop)
+            continue;
+          if (DefLoop->contains(L))
             return true;
+        }
       }
     }
   }