enable nvfuser matmul

thunder/executors/nvfuserex_impl.py

@@ -1948,6 +1948,28 @@ def var_mean(
 
 register_supported(PrimIDs.VAR_MEAN, var_mean, _var_mean_check)
 
+def _matmul_check(
+    a: TensorProxy,
+    b: TensorProxy,
+) -> bool:
+    enable_matmul: None | bool = get_compile_option("nv_enable_matmul", "Enable nvFuser matmul.")
+    if enable_matmul is None:
+        enable_matmul = False
+    return enable_matmul and is_supported_tensor(a) and is_supported_tensor(b)
+
+def matmul(
+    a: TensorProxy,
+    b: TensorProxy,
+    *,
+    fd: FusionDefinition,
+    lc_to_nv_map: dict,
+) -> Any:
+    nva = getnv(a, fd, lc_to_nv_map)
+    nvb = getnv(b, fd, lc_to_nv_map)
+    return fd.ops.matmul(nva, nvb)
+
+register_supported(PrimIDs.MATMUL, matmul, _matmul_check)
+
 
 # Removes excessive float casts, like those that occur when autocasting
 # NOTE This passes actually changes a program's semantics, because it will take a sequence like