[polly] [Polly] Add vectorize metadata to loops identified as vectorizable by polly (PR #113994)

[Michael Kruse via llvm-commits]

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@@ -233,6 +238,26 @@ 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-annotate-metadata-vectorize' is passed.
+  if (PollyVectorizeMetadata) {
+    for (Loop *L : LI.getLoopsInPreorder()) {
+      if (S.contains(L)) {
+        Annotator.pushLoop(L, false);
+        SmallVector<BasicBlock *> LoopLatchBlocks;
+        L->getLoopLatches(LoopLatchBlocks);
+        for (BasicBlock *ControlBB : LoopLatchBlocks) {
+          BranchInst *Br = dyn_cast<BranchInst>(ControlBB->getTerminator());
+          if (Br)
+            Annotator.annotateLoopLatch(Br, L, false, true, false);
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Meinersbur wrote:

Why not directly calling `addVectorizeMetadata` here? The ScopAnnotator was design with the assumption to be called on generated code only. Using it outside of it may result in unexpected situations.

https://github.com/llvm/llvm-project/pull/113994