[llvm] [IR] Add `llvm.sincos` intrinsic (PR #109825)

[Matt Arsenault via llvm-commits]

================
@@ -6918,12 +6918,23 @@ void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
                              getValue(I.getArgOperand(0)),
                              getValue(I.getArgOperand(1)), Flags));
     return;
+  case Intrinsic::sincos:
   case Intrinsic::frexp: {
+    unsigned Opcode;
+    switch (Intrinsic) {
+    default:
+      llvm_unreachable("unexpected intrinsic");
+    case Intrinsic::sincos:
+      Opcode = ISD::FSINCOS;
+      break;
+    case Intrinsic::frexp:
+      Opcode = ISD::FFREXP;
+      break;
+    }
     SmallVector<EVT, 2> ValueVTs;
     ComputeValueVTs(TLI, DAG.getDataLayout(), I.getType(), ValueVTs);
     SDVTList VTs = DAG.getVTList(ValueVTs);
-    setValue(&I,
-             DAG.getNode(ISD::FFREXP, sdl, VTs, getValue(I.getArgOperand(0))));
+    setValue(&I, DAG.getNode(Opcode, sdl, VTs, getValue(I.getArgOperand(0))));
----------------
arsenm wrote:

Flags lost? 

https://github.com/llvm/llvm-project/pull/109825