[llvm] [SLP] More accurately cost RISCV scalar splats (PR #213104)

[Alexey Bataev via llvm-commits]

================
@@ -3594,6 +3609,31 @@ bool RISCVTTIImpl::canSplatOperand(Instruction *I, int Operand) const {
   }
 }
 
+TargetTransformInfo::VectorInstrContext RISCVTTIImpl::getBuildVectorContextHint(
+    ArrayRef<int> Mask, ArrayRef<Value *> Scalars,
+    function_ref<bool(SmallVectorImpl<TargetTransformInfo::BuildVectorUseOp> &)>
+        GatherUseOps) const {
+  if (Scalars.empty() ||
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alexey-bataev wrote:

```suggestion
  if (Scalars.empty() || !ST->sinkSplatOperands() ||
```

https://github.com/llvm/llvm-project/pull/213104