[llvm] [AArch64] Avoid streaming mode hazards from FP constant stores (PR #114207)

[Benjamin Maxwell via llvm-commits]

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@@ -22514,14 +22514,22 @@ static SDValue performSTNT1Combine(SDNode *N, SelectionDAG &DAG) {
 ///   movi v0.2d, #0
 ///   str q0, [x0]
 ///
-static SDValue replaceZeroVectorStore(SelectionDAG &DAG, StoreSDNode &St) {
+static SDValue replaceZeroVectorStore(SelectionDAG &DAG, StoreSDNode &St,
+                                      AArch64Subtarget const &Subtarget) {
   SDValue StVal = St.getValue();
   EVT VT = StVal.getValueType();
 
   // Avoid scalarizing zero splat stores for scalable vectors.
   if (VT.isScalableVector())
     return SDValue();
 
+  // Do not replace the FP store when it could result in a streaming memory
+  // hazard.
+  if (VT.getVectorElementType().isFloatingPoint() &&
+      Subtarget.getStreamingHazardSize() > 0 &&
+      (Subtarget.isStreaming() || Subtarget.isStreamingCompatible()))
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MacDue wrote:

Yep, done :+1: 

https://github.com/llvm/llvm-project/pull/114207