Update clang/lib/CodeGen/BackendUtil.cpp

Update comments.

Co-authored-by: Victor Lomuller <[email protected]>

Author: jsji

clang/lib/CodeGen/BackendUtil.cpp

@@ -1046,8 +1046,8 @@ void EmitAssemblyHelper::RunOptimizationPipeline(
       PB.registerOptimizerEarlyEPCallback([](ModulePassManager &MPM,
                                              OptimizationLevel Level,
                                              ThinOrFullLTOPhase) {
-        // Allocate static local memory in SYCL kernel scope for each allocation
-        // call.
+        // Lowers __sycl_allocateLocalMemory  and __sycl_dynamicLocalMemoryPlaceholder
+        // builtin calls.
         MPM.addPass(SYCLLowerWGLocalMemoryPass());
       });
     } else if (LangOpts.SYCLIsHost && !LangOpts.SYCLESIMDBuildHostCode)