[llvm] [ISel] Introduce llvm.clmul intrinsic (PR #168731)

[Piotr Fusik via llvm-commits]

================
@@ -919,6 +919,11 @@ inline BinaryOpc_match<LHS, RHS> m_Rotr(const LHS &L, const RHS &R) {
   return BinaryOpc_match<LHS, RHS>(ISD::ROTR, L, R);
 }
 
+template <typename LHS, typename RHS>
+inline BinaryOpc_match<LHS, RHS> m_Clmul(const LHS &L, const RHS &R) {
+  return BinaryOpc_match<LHS, RHS>(ISD::CLMUL, L, R);
----------------
pfusik wrote:

```suggestion
  return BinaryOpc_match<LHS, RHS, true>(ISD::CLMUL, L, R);
```
because it's commutative.

https://github.com/llvm/llvm-project/pull/168731