1 files changed, 15 insertions, 9 deletions
diff --git a/polly/lib/CodeGen/CodeGeneration.cpp b/polly/lib/CodeGen/CodeGeneration.cpp
index 2d8b393..062cdfb 100644
--- a/polly/lib/CodeGen/CodeGeneration.cpp
+++ b/polly/lib/CodeGen/CodeGeneration.cpp
@@ -235,15 +235,6 @@ static bool generateCode(Scop &S, IslAstInfo &AI, LoopInfo &LI,
   NodeBuilder.allocateNewArrays(StartExitBlocks);
   Annotator.buildAliasScopes(S);
 
-  // The code below annotates the "llvm.loop.vectorize.enable" to false
-  // for the code flow taken when RTCs fail. Because we don't want the
-  // Loop Vectorizer to come in later and vectorize the original fall back
-  // loop when Polly is enabled.
-  for (Loop *L : LI.getLoopsInPreorder()) {
-    if (S.contains(L))
-      addStringMetadataToLoop(L, "llvm.loop.vectorize.enable", 0);
-  }
-
   if (PerfMonitoring) {
     PerfMonitor P(S, EnteringBB->getParent()->getParent());
     P.initialize();
@@ -285,6 +276,21 @@ static bool generateCode(Scop &S, IslAstInfo &AI, LoopInfo &LI,
 
     Builder.GetInsertBlock()->getTerminator()->setOperand(0, RTC);
 
+    auto *CI = dyn_cast<ConstantInt>(RTC);
+    // The code below annotates the "llvm.loop.vectorize.enable" to false
+    // for the code flow taken when RTCs fail. Because we don't want the
+    // Loop Vectorizer to come in later and vectorize the original fall back
+    // loop when Polly is enabled. This avoids loop versioning on fallback
+    // loop by Loop Vectorizer. Don't do this when Polly's RTC value is
+    // false (due to code generation failure), as we are left with only one
+    // version of Loop.
+    if (!(CI && CI->isZero())) {
+      for (Loop *L : LI.getLoopsInPreorder()) {
+        if (S.contains(L))
+          addStringMetadataToLoop(L, "llvm.loop.vectorize.enable", 0);
+      }
+    }
+
     // Explicitly set the insert point to the end of the block to avoid that a
     // split at the builder's current
     // insert position would move the malloc calls to the wrong BasicBlock.