Do not mark GC vars live across an unmanged call as DNER in liveness for RyuJIT.

The RA inserts kills that ensure that live variables are not enregistered across
unmanaged calls, so this is not necessary.

diff --git a/src/jit/liveness.cpp b/src/jit/liveness.cpp
index 65cec0d..a541417 100644 (file)
--- a/src/jit/liveness.cpp
+++ b/src/jit/liveness.cpp
@@ -1578,13 +1578,14 @@ void Compiler::fgComputeLifeCall(VARSET_TP& life, GenTreeCall* call)
             }
         }
 
+#ifdef LEGACY_BACKEND
         /* Do we have any live variables? */
-
         if (!VarSetOps::IsEmpty(this, life))
         {
-            // For each live variable if it is a GC-ref type, we
-            // mark it volatile to prevent if from being enregistered
+            // For each live variable if it is a GC-ref type, mark it volatile to prevent if from being enregistered
             // across the unmanaged call.
+            //
+            // Note that this is not necessary when targeting the RyuJIT backend, as its RA handles these kills itself.
 
             unsigned   lclNum;
             LclVarDsc* varDsc;
@@ -1613,6 +1614,7 @@ void Compiler::fgComputeLifeCall(VARSET_TP& life, GenTreeCall* call)
                 }
             }
         }
+#endif // LEGACY_BACKEND
     }
 }