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

[Craig Topper via llvm-commits]

================
@@ -1070,6 +1070,13 @@ class RISCVTargetLowering : public TargetLowering {
     return false;
   }
 
+  /// Disables storing and loading vectors by default when there are function
+  /// calls between the load and store, since these are more expensive than just
+  /// using scalars
+  bool shouldMergeStoreOfLoadsOverCall(EVT SrcVT, EVT MergedVT) const override {
+    return SrcVT.isScalarInteger() == MergedVT.isScalarInteger();
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topperc wrote:

I think SrcVT can be a scalar FP and MergeVT can be a scalar integer VT. In that case it would still be ok to merge across the call.

Maybe this should be

```
  return !MergedVT.isVector() || SrcVT.isVector();
```

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