[llvm] Add `llvm.vector.partial.reduce.fadd` intrinsic (PR #159776)

[Sander de Smalen via llvm-commits]

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@@ -13070,22 +13076,26 @@ SDValue DAGCombiner::foldPartialReduceAdd(SDNode *N) {
 
   APInt ConstantOne;
   if (!ISD::isConstantSplatVector(Op2.getNode(), ConstantOne) ||
-      !ConstantOne.isOne())
+      !(ConstantOne.isOne() ||
+        ConstantOne ==
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sdesmalen-arm wrote:

nit: the casting here looks a bit odd, and I'm not sure this always works. Can you instead separate out the cases for int and FP and use `llvm::isConstOrConstSplatFP` for the latter (you can check the result using `isExactlyValue(1)`).

https://github.com/llvm/llvm-project/pull/159776