[llvm] [RISCV] Reduce LMUL when index is known when lowering insert_vector_elt (PR #66087)

[Craig Topper via llvm-commits]

================
@@ -7401,6 +7401,19 @@ SDValue RISCVTargetLowering::lowerINSERT_VECTOR_ELT(SDValue Op,
     Vec = convertToScalableVector(ContainerVT, Vec, DAG, Subtarget);
   }
 
+  MVT OrigContainerVT = ContainerVT;
+  SDValue OrigVec = Vec;
+  // If we know the index we're going to insert at, we can shrink down Vec so
+  // we're performing the vslide1down on a smaller LMUL.
----------------
topperc wrote:

vslide1down? shouldn't that be vslideup?

https://github.com/llvm/llvm-project/pull/66087