[llvm] [AArch64] Lower partial add reduction to udot or svdot (PR #101010)

[Sam Tebbs via llvm-commits]

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@@ -1971,6 +1971,48 @@ bool AArch64TargetLowering::shouldExpandGetActiveLaneMask(EVT ResVT,
   return false;
 }
 
+bool AArch64TargetLowering::shouldExpandPartialReductionIntrinsic(
+    const IntrinsicInst *I) const {
+
+  VectorType *RetTy = dyn_cast<VectorType>(I->getType());
+  if (!RetTy || !RetTy->isScalableTy())
+    return true;
+
+  Value *InputA;
+  Value *InputB;
+  if (match(I,
+            m_Intrinsic<Intrinsic::experimental_vector_partial_reduce_add>(
+                m_Value(), m_OneUse(m_Mul(m_ZExtOrSExt(m_Value(InputA)),
+                                          m_ZExtOrSExt(m_Value(InputB))))))) {
+    VectorType *InputAType = dyn_cast<VectorType>(InputA->getType());
+    VectorType *InputBType = dyn_cast<VectorType>(InputB->getType());
+    if (!InputAType || !InputBType)
+      return true;
----------------
SamTebbs33 wrote:

Thanks Paul, I like the approach of sharing the expansion code in SelectionDAG. Let me know what you think of the new implementation.

https://github.com/llvm/llvm-project/pull/101010