[llvm] [SelectionDAG][RISCV] Avoid store merging across function calls (PR #130430)

[Mikhail R. Gadelha via llvm-commits]

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@@ -21553,6 +21553,56 @@ bool DAGCombiner::tryStoreMergeOfLoads(SmallVectorImpl<MemOpLink> &StoreNodes,
       JointMemOpVT = EVT::getIntegerVT(Context, SizeInBits);
     }
 
+    auto HasCallInLdStChain = [](SmallVectorImpl<MemOpLink> &StoreNodes,
+                                 SmallVectorImpl<MemOpLink> &LoadNodes,
+                                 unsigned NumStores) {
+      for (unsigned i = 0; i < NumStores; ++i) {
+        StoreSDNode *St = cast<StoreSDNode>(StoreNodes[i].MemNode);
+        SDValue Val = peekThroughBitcasts(St->getValue());
+        LoadSDNode *Ld = cast<LoadSDNode>(Val);
+        assert(Ld == LoadNodes[i].MemNode && "Load and store mismatch");
+
+        SmallPtrSet<const SDNode *, 32> Visited;
+        SmallVector<std::pair<const SDNode *, bool>, 8> Worklist;
+        Worklist.emplace_back(St->getOperand(0).getNode(), false);
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mikhailramalho wrote:

We would need to cast it to a `MemSDNode`, since `getChain()` is not part of `SDNode`, and it would only work on load/store instruction...

https://github.com/llvm/llvm-project/pull/130430