small code quality improvements

Author: ZuseZ4

compiler/rustc_codegen_llvm/src/builder/autodiff.rs

@@ -276,7 +276,7 @@ fn generate_enzyme_call<'ll>(
 }
 
 pub(crate) fn differentiate<'ll>(
-    module: &'ll ModuleCodegen<ModuleLlvm>,
+    module_llvm: &'ll ModuleLlvm,
     cgcx: &CodegenContext<LlvmCodegenBackend>,
     diff_items: Vec<AutoDiffItem>,
     _config: &ModuleConfig,
@@ -286,7 +286,7 @@ pub(crate) fn differentiate<'ll>(
     }
 
     let diag_handler = cgcx.create_dcx();
-    let cx = SimpleCx { llmod: module.module_llvm.llmod(), llcx: module.module_llvm.llcx };
+    let cx = SimpleCx { llmod: module_llvm.llmod(), llcx: module_llvm.llcx };
 
     // First of all, did the user try to use autodiff without using the -Zautodiff=Enable flag?
     if !diff_items.is_empty()

compiler/rustc_codegen_llvm/src/lib.rs

@@ -241,7 +241,8 @@ impl WriteBackendMethods for LlvmCodegenBackend {
             let dcx = cgcx.create_dcx();
             return Err(dcx.handle().emit_almost_fatal(AutoDiffWithoutLTO));
         }
-        builder::autodiff::differentiate(module, cgcx, diff_fncs, config)
+        let module_llvm = &module.module_llvm;
+        builder::autodiff::differentiate(module_llvm, cgcx, diff_fncs, config)
     }
 }
 

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -1473,13 +1473,14 @@ fn start_executing_work<B: ExtraBackendMethods>(
                     assert!(!started_lto);
                     started_lto = true;
 
+                    let autodiff_items = mem::take(&mut autodiff_items);
                     let needs_fat_lto = mem::take(&mut needs_fat_lto);
                     let needs_thin_lto = mem::take(&mut needs_thin_lto);
                     let import_only_modules = mem::take(&mut lto_import_only_modules);
 
                     for (work, cost) in generate_lto_work(
                         &cgcx,
-                        autodiff_items.clone(),
+                        autodiff_items,
                         needs_fat_lto,
                         needs_thin_lto,
                         import_only_modules,