3 files changed, 13 insertions, 7 deletions
diff --git a/llvm/lib/Analysis/GuardUtils.cpp b/llvm/lib/Analysis/GuardUtils.cpp
index cad92f6e56b..863443cea35 100644
--- a/llvm/lib/Analysis/GuardUtils.cpp
+++ b/llvm/lib/Analysis/GuardUtils.cpp
@@ -42,6 +42,11 @@ bool llvm::parseWidenableBranch(const User *U, Value *&Condition,
   if (!match(U, m_Br(m_And(m_Value(Condition), m_Value(WidenableCondition)),
                      IfTrueBB, IfFalseBB)))
     return false;
+  // For the branch to be (easily) widenable, it must not correlate with other
+  // branches.  Thus, the widenable condition must have a single use.
+  if (!WidenableCondition->hasOneUse() ||
+      !cast<BranchInst>(U)->getCondition()->hasOneUse())
+    return false;
   // TODO: At the moment, we only recognize the branch if the WC call in this
   // specific position.  We should generalize!
   return match(WidenableCondition,
diff --git a/llvm/lib/Transforms/Scalar/GuardWidening.cpp b/llvm/lib/Transforms/Scalar/GuardWidening.cpp
index 2697d780956..269e641b8f1 100644
--- a/llvm/lib/Transforms/Scalar/GuardWidening.cpp
+++ b/llvm/lib/Transforms/Scalar/GuardWidening.cpp
@@ -271,16 +271,17 @@ class GuardWideningImpl {
   void widenGuard(Instruction *ToWiden, Value *NewCondition,
                   bool InvertCondition) {
     Value *Result;
+    
     widenCondCommon(getCondition(ToWiden), NewCondition, ToWiden, Result,
                     InvertCondition);
-    Value *WidenableCondition = nullptr;
     if (isGuardAsWidenableBranch(ToWiden)) {
-      auto *Cond = cast<BranchInst>(ToWiden)->getCondition();
-      WidenableCondition = cast<BinaryOperator>(Cond)->getOperand(1);
+      auto *BI = cast<BranchInst>(ToWiden);
+      auto *And = cast<Instruction>(BI->getCondition());
+      And->setOperand(0, Result);
+      And->moveBefore(ToWiden);
+      assert(isGuardAsWidenableBranch(ToWiden) && "still widenable?");
+      return;
     }
-    if (WidenableCondition)
-      Result = BinaryOperator::CreateAnd(Result, WidenableCondition,
-                                         "guard.chk", ToWiden);
     setCondition(ToWiden, Result);
   }
 
diff --git a/llvm/lib/Transforms/Scalar/LoopPredication.cpp b/llvm/lib/Transforms/Scalar/LoopPredication.cpp
index 885c0e8f4b8..495f0bc83d6 100644
--- a/llvm/lib/Transforms/Scalar/LoopPredication.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopPredication.cpp
@@ -823,9 +823,9 @@ bool LoopPredication::widenWidenableBranchGuardConditions(
   Value *AllChecks = Builder.CreateAnd(Checks);
   auto *OldCond = BI->getCondition();
   BI->setCondition(AllChecks);
+  RecursivelyDeleteTriviallyDeadInstructions(OldCond);
   assert(isGuardAsWidenableBranch(BI) &&
          "Stopped being a guard after transform?");
-  RecursivelyDeleteTriviallyDeadInstructions(OldCond);
 
   LLVM_DEBUG(dbgs() << "Widened checks = " << NumWidened << "\n");
   return true;