[llvm] [RISCV][GISel] Add initial support for rvv intrinsics (PR #156415)

[Jon Roelofs via llvm-commits]

================
@@ -24700,6 +24700,18 @@ bool RISCVTargetLowering::fallBackToDAGISel(const Instruction &Inst) const {
       Op == Instruction::Freeze || Op == Instruction::Store)
     return false;
 
+  if (Op == Instruction::Call) {
+    const CallInst &CI = cast<CallInst>(Inst);
+    const Function *F = CI.getCalledFunction();
+    Intrinsic::ID ID = F ? F->getIntrinsicID() : Intrinsic::not_intrinsic;
+
+    const RISCVVIntrinsicsTable::RISCVVIntrinsicInfo *II =
+        RISCVVIntrinsicsTable::getRISCVVIntrinsicInfo(ID);
+    // Mark RVV intrinsic is supported.
+    if (II)
+      return false;
+  }
----------------
jroelofs wrote:

```suggestion
  if (auto *II = dyn_cast<IntrinsicInst>(&Inst)) {
    // Mark RVV intrinsic as supported.
    if (RISCVVIntrinsicsTable::getRISCVVIntrinsicInfo(II->getIntrinsicID()))
      return false;
  }
```

https://github.com/llvm/llvm-project/pull/156415