diff --git a/src/CodeGen_Internal.cpp b/src/CodeGen_Internal.cpp
index 903f7768ca65..5c36ea58aae3 100644
--- a/src/CodeGen_Internal.cpp
+++ b/src/CodeGen_Internal.cpp
@@ -666,12 +666,17 @@ std::unique_ptr<llvm::TargetMachine> make_target_machine(const llvm::Module &mod
     bool use_large_code_model = false;
     get_md_bool(module.getModuleFlag("halide_use_large_code_model"), use_large_code_model);
 
+#if LLVM_VERSION >= 180
+    const auto opt_level = llvm::CodeGenOptLevel::Aggressive;
+#else
+    const auto opt_level = llvm::CodeGenOpt::Aggressive;
+#endif
     auto *tm = llvm_target->createTargetMachine(module.getTargetTriple(),
                                                 /*CPU target=*/"", /*Features=*/"",
                                                 options,
                                                 use_pic ? llvm::Reloc::PIC_ : llvm::Reloc::Static,
                                                 use_large_code_model ? llvm::CodeModel::Large : llvm::CodeModel::Small,
-                                                llvm::CodeGenOpt::Aggressive);
+                                                opt_level);
     return std::unique_ptr<llvm::TargetMachine>(tm);
 }
 
diff --git a/src/CodeGen_PTX_Dev.cpp b/src/CodeGen_PTX_Dev.cpp
index 2793457ccec9..2a47e591c503 100644
--- a/src/CodeGen_PTX_Dev.cpp
+++ b/src/CodeGen_PTX_Dev.cpp
@@ -623,12 +623,17 @@ vector<char> CodeGen_PTX_Dev::compile_to_src() {
     options.NoZerosInBSS = false;
     options.GuaranteedTailCallOpt = false;
 
+#if LLVM_VERSION >= 180
+    const auto opt_level = CodeGenOptLevel::Aggressive;
+#else
+    const auto opt_level = CodeGenOpt::Aggressive;
+#endif
     std::unique_ptr<TargetMachine>
         target_machine(llvm_target->createTargetMachine(triple.str(),
                                                         mcpu_target(), mattrs(), options,
                                                         llvm::Reloc::PIC_,
                                                         llvm::CodeModel::Small,
-                                                        CodeGenOpt::Aggressive));
+                                                        opt_level));
 
     internal_assert(target_machine.get()) << "Could not allocate target machine!";
 
@@ -724,10 +729,14 @@ vector<char> CodeGen_PTX_Dev::compile_to_src() {
 
     // Output string stream
 
+#if LLVM_VERSION >= 180
+    const auto file_type = ::llvm::CodeGenFileType::AssemblyFile;
+#else
+    const auto file_type = ::llvm::CGFT_AssemblyFile;
+#endif
     // Ask the target to add backend passes as necessary.
     bool fail = target_machine->addPassesToEmitFile(module_pass_manager, ostream, nullptr,
-                                                    ::llvm::CGFT_AssemblyFile,
-                                                    true);
+                                                    file_type, true);
     internal_assert(!fail) << "Failed to set up passes to emit PTX source\n";
     module_pass_manager.run(*module);
 
diff --git a/src/JITModule.cpp b/src/JITModule.cpp
index 169f96acfcbc..eb274bc6c59d 100644
--- a/src/JITModule.cpp
+++ b/src/JITModule.cpp
@@ -334,7 +334,11 @@ void JITModule::compile_module(std::unique_ptr<llvm::Module> m, const string &fu
     // Build TargetMachine
     llvm::orc::JITTargetMachineBuilder tm_builder(llvm::Triple(m->getTargetTriple()));
     tm_builder.setOptions(options);
+#if LLVM_VERSION >= 180
+    tm_builder.setCodeGenOptLevel(CodeGenOptLevel::Aggressive);
+#else
     tm_builder.setCodeGenOptLevel(CodeGenOpt::Aggressive);
+#endif
     if (target.arch == Target::Arch::RISCV) {
         tm_builder.setCodeModel(llvm::CodeModel::Medium);
     }
diff --git a/src/LLVM_Output.cpp b/src/LLVM_Output.cpp
index 04af5aff3609..4952fc981877 100644
--- a/src/LLVM_Output.cpp
+++ b/src/LLVM_Output.cpp
@@ -425,11 +425,19 @@ std::unique_ptr<llvm::Module> compile_module_to_llvm_module(const Module &module
 }
 
 void compile_llvm_module_to_object(llvm::Module &module, Internal::LLVMOStream &out) {
+#if LLVM_VERSION >= 180
+    emit_file(module, out, llvm::CodeGenFileType::ObjectFile);
+#else
     emit_file(module, out, llvm::CGFT_ObjectFile);
+#endif
 }
 
 void compile_llvm_module_to_assembly(llvm::Module &module, Internal::LLVMOStream &out) {
+#if LLVM_VERSION >= 180
+    emit_file(module, out, llvm::CodeGenFileType::AssemblyFile);
+#else
     emit_file(module, out, llvm::CGFT_AssemblyFile);
+#endif
 }
 
 void compile_llvm_module_to_llvm_bitcode(llvm::Module &module, Internal::LLVMOStream &out) {