[llvm] [LV] Support multiplies by constants when forming scaled reductions. (PR #161092)

[Florian Hahn via llvm-commits]

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@@ -7954,6 +7954,13 @@ bool VPRecipeBuilder::getScaledReductions(
   auto CollectExtInfo = [this, &Exts, &ExtOpTypes,
                          &ExtKinds](SmallVectorImpl<Value *> &Ops) -> bool {
     for (const auto &[I, OpI] : enumerate(Ops)) {
+      auto *CI = dyn_cast<ConstantInt>(OpI);
+      if (I > 0 && CI &&
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fhahn wrote:

We can't drop the first operand, as it needs to be handled below.

https://github.com/llvm/llvm-project/pull/161092