1 files changed, 14 insertions, 0 deletions

diff --git a/contrib/llvm-project/llvm/lib/Transforms/Scalar/LoopFuse.cpp b/contrib/llvm-project/llvm/lib/Transforms/Scalar/LoopFuse.cpp
index b5f8dfa9aafb..ca19913e37ee 100644
--- a/contrib/llvm-project/llvm/lib/Transforms/Scalar/LoopFuse.cpp
+++ b/contrib/llvm-project/llvm/lib/Transforms/Scalar/LoopFuse.cpp
@@ -99,6 +99,8 @@ STATISTIC(NonEmptyExitBlock, "Candidate has a non-empty exit block with "
 STATISTIC(NonEmptyGuardBlock, "Candidate has a non-empty guard block with "
                               "instructions that cannot be moved");
 STATISTIC(NotRotated, "Candidate is not rotated");
+STATISTIC(OnlySecondCandidateIsGuarded,
+          "The second candidate is guarded while the first one is not");
 
 enum FusionDependenceAnalysisChoice {
   FUSION_DEPENDENCE_ANALYSIS_SCEV,
@@ -370,11 +372,13 @@ private:
   bool reportInvalidCandidate(llvm::Statistic &Stat) const {
     using namespace ore;
     assert(L && Preheader && "Fusion candidate not initialized properly!");
+#if LLVM_ENABLE_STATS
     ++Stat;
     ORE.emit(OptimizationRemarkAnalysis(DEBUG_TYPE, Stat.getName(),
                                         L->getStartLoc(), Preheader)
              << "[" << Preheader->getParent()->getName() << "]: "
              << "Loop is not a candidate for fusion: " << Stat.getDesc());
+#endif
     return false;
   }
 };
@@ -891,6 +895,14 @@ private:
             continue;
           }
 
+          if (!FC0->GuardBranch && FC1->GuardBranch) {
+            LLVM_DEBUG(dbgs() << "The second candidate is guarded while the "
+                                 "first one is not. Not fusing.\n");
+            reportLoopFusion<OptimizationRemarkMissed>(
+                *FC0, *FC1, OnlySecondCandidateIsGuarded);
+            continue;
+          }
+
           // Ensure that FC0 and FC1 have identical guards.
           // If one (or both) are not guarded, this check is not necessary.
           if (FC0->GuardBranch && FC1->GuardBranch &&
@@ -1523,6 +1535,7 @@ private:
     assert(FC0.Preheader && FC1.Preheader &&
            "Expecting valid fusion candidates");
     using namespace ore;
+#if LLVM_ENABLE_STATS
     ++Stat;
     ORE.emit(RemarkKind(DEBUG_TYPE, Stat.getName(), FC0.L->getStartLoc(),
                         FC0.Preheader)
@@ -1530,6 +1543,7 @@ private:
              << "]: " << NV("Cand1", StringRef(FC0.Preheader->getName()))
              << " and " << NV("Cand2", StringRef(FC1.Preheader->getName()))
              << ": " << Stat.getDesc());
+#endif
   }
 
   /// Fuse two guarded fusion candidates, creating a new fused loop.