[llvm] [LV] Autovectorization for the all-in-one histogram intrinsic (PR #91458)

[Florian Hahn via llvm-commits]

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@@ -869,6 +870,42 @@ void VPWidenCallRecipe::print(raw_ostream &O, const Twine &Indent,
     O << ")";
   }
 }
+#endif
+
+void VPHistogramRecipe::execute(VPTransformState &State) {
+  assert(State.UF == 1 && "Tried interleaving histogram operation");
+  State.setDebugLocFrom(getDebugLoc());
+  IRBuilderBase &Builder = State.Builder;
+  Value *Address = State.get(getOperand(0), 0);
+  Value *IncVec = State.get(getOperand(1), 0);
+  Value *Mask = State.get(getOperand(2), 0);
+
+  // Not sure how to make IncAmt stay scalar yet. For now just extract the
+  // first element and tidy up later.
+  // FIXME: Do we actually want this to be scalar? We just splat it in the
+  //        backend anyway...
+  Value *IncAmt = Builder.CreateExtractElement(IncVec, Builder.getInt64(0));
+
+  // If this is a subtract, we want to invert the increment amount. We may
+  // add a separate intrinsic in future, but for now we'll try this.
+  if (Opcode == Instruction::Sub)
+    IncAmt = Builder.CreateNeg(IncAmt);
+
+  State.Builder.CreateIntrinsic(Intrinsic::experimental_vector_histogram_add,
+                                {Address->getType(), IncAmt->getType()},
+                                {Address, IncAmt, Mask});
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void VPHistogramRecipe::print(raw_ostream &O, const Twine &Indent,
+                              VPSlotTracker &SlotTracker) const {
+  O << Indent << "WIDEN-HISTOGRAM buckets: ";
+  getOperand(0)->printAsOperand(O, SlotTracker);
+  O << ", inc: ";
+  getOperand(1)->printAsOperand(O, SlotTracker);
+  O << ", mask: ";
+  getOperand(2)->printAsOperand(O, SlotTracker);
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fhahn wrote:

Test missing?

https://github.com/llvm/llvm-project/pull/91458