[llvm] [SDAG] Allow folding stack slots into sincos/frexp in more cases (PR #118117)

[Matt Arsenault via llvm-commits]

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@@ -2502,11 +2541,7 @@ bool SelectionDAG::expandMultipleResultFPLibCall(
 
   // Find users of the node that store the results (and share input chains). The
   // destination pointers can be used instead of creating stack allocations.
-  // FIXME: This should allow stores with the same chains (not just the entry
-  // chain), but there's a risk the store is within a (CALLSEQ_START,
-  // CALLSEQ_END) pair, which after this expansion will lead to nested call
-  // sequences.
-  SDValue InChain = getEntryNode();
+  SDValue StoresInChain{};
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arsenm wrote:

```suggestion
  SDValue StoresInChain;
```

https://github.com/llvm/llvm-project/pull/118117