[llvm] [LV] Vectorize conditional scalar assignments (PR #158088)

[Florian Hahn via llvm-commits]

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@@ -10148,6 +10167,21 @@ bool LoopVectorizePass::processLoop(Loop *L) {
   // Override IC if user provided an interleave count.
   IC = UserIC > 0 ? UserIC : IC;
 
+  // FIXME: Enable interleaving for last_active reductions.
+  if (any_of(LVL.getReductionVars().values(), [](auto &RdxDesc) {
+        return RecurrenceDescriptor::isFindLastRecurrenceKind(
+            RdxDesc.getRecurrenceKind());
+      })) {
+    LLVM_DEBUG(dbgs() << "LV: Not interleaving without vectorization due "
+                      << "to conditional scalar assignments.\n");
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fhahn wrote:

```suggestion
                      << "to FindLast reduction.\n");
```

for consistency with the reduction naming

https://github.com/llvm/llvm-project/pull/158088