[SYCL] Call getenv/stoi only once (#7308)

Signed-off-by: Sergey V Maslov <[email protected]>

Author: smaslov-intel

sycl/plugins/level_zero/pi_level_zero.cpp

@@ -6913,6 +6913,13 @@ pi_result piEnqueueMemBufferCopyRect(
 
 } // extern "C"
 
+// Default to using compute engine for fill operation, but allow to
+// override this with an environment variable.
+static bool PreferCopyEngine = [] {
+  const char *Env = std::getenv("SYCL_PI_LEVEL_ZERO_USE_COPY_ENGINE_FOR_FILL");
+  return Env ? std::stoi(Env) != 0 : false;
+}();
+
 // PI interfaces must have queue's and buffer's mutexes locked on entry.
 static pi_result
 enqueueMemFillHelper(pi_command_type CommandType, pi_queue Queue, void *Ptr,
@@ -6926,13 +6933,6 @@ enqueueMemFillHelper(pi_command_type CommandType, pi_queue Queue, void *Ptr,
 
   auto &Device = Queue->Device;
 
-  // Default to using compute engine for fill operation, but allow to
-  // override this with an environment variable.
-  const char *PreferCopyEngineEnv =
-      std::getenv("SYCL_PI_LEVEL_ZERO_USE_COPY_ENGINE_FOR_FILL");
-  bool PreferCopyEngine =
-      PreferCopyEngineEnv ? std::stoi(PreferCopyEngineEnv) != 0 : false;
-
   // Make sure that pattern size matches the capability of the copy queues.
   // Check both main and link groups as we don't known which one will be used.
   //