[llvm] [LV] Emit better debug and opt-report messages when vectorization is disallowed in the LoopVectorizer (PR #158513)

[Tibor Győri via llvm-commits]

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@@ -182,14 +182,41 @@ void LoopVectorizeHints::setAlreadyVectorized() {
 bool LoopVectorizeHints::allowVectorization(
     Function *F, Loop *L, bool VectorizeOnlyWhenForced) const {
   if (getForce() == LoopVectorizeHints::FK_Disabled) {
-    LLVM_DEBUG(dbgs() << "LV: Not vectorizing: #pragma vectorize disable.\n");
-    emitRemarkWithHints();
+    if (Force.Value == LoopVectorizeHints::FK_Disabled) {
+      LLVM_DEBUG(dbgs() << "LV: Not vectorizing: #pragma vectorize disable.\n");
+      ORE.emit(OptimizationRemarkMissed(LV_NAME, "MissedExplicitlyDisabled",
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TiborGY wrote:

I am planning to refactor and rename emitRemarkWithHints in a future PR. Its name does not reflect well what it is doing and it does not let the caller emit a remark more specific than "loop not vectorized". So for now, I have inlined the relevant part of emitRemarkWithHints here.

https://github.com/llvm/llvm-project/pull/158513