[llvm] [llvm][CodeGen] Intrinsic `llvm.powi/ldexp.*` code gen for vector arguments (PR #118242)

[Zhaoxin Yang via llvm-commits]

================
@@ -2585,6 +2585,8 @@ SDValue DAGTypeLegalizer::PromoteIntOp_ExpOp(SDNode *N) {
                              : RTLIB::getLDEXP(N->getValueType(0));
 
   if (LC == RTLIB::UNKNOWN_LIBCALL || !TLI.getLibcallName(LC)) {
+    if (N->getValueType(0).isVector())
+      return DAG.UnrollVectorOp(N);
----------------
ylzsx wrote:

> This whole function is actually the wrong place to split the vector (see how there are no other UnrollVectorOps uses in DAGTypeLegalizer). The description also says your problem is when the libcall is used, so you'd want to change the other path? Does the libcall emission below need to directly handle the vector case?

@topperc what are your thoughts on this?

https://github.com/llvm/llvm-project/pull/118242