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

[Sam Tebbs via llvm-commits]

================
@@ -2515,13 +2550,25 @@ bool SelectionDAG::expandMultipleResultFPLibCall(
     SDValue StoreValue = ST->getValue();
     unsigned ResNo = StoreValue.getResNo();
     Type *StoreType = StoreValue.getValueType().getTypeForEVT(Ctx);
-    if (CallRetResNo == ResNo || !ST->isSimple() ||
+    if (
+        // Ensure the store corresponds to an output pointer.
----------------
SamTebbs33 wrote:

I think it would be better to set some bool variables, put comments above those, and use them in the if statement.

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