diff --git a/clif/backend/matcher.cc b/clif/backend/matcher.cc
index 0add125c..a0300fe3 100644
--- a/clif/backend/matcher.cc
+++ b/clif/backend/matcher.cc
@@ -39,10 +39,6 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 
-#ifndef PYCLIF_LLVM_VERSION_MAJOR
-#define PYCLIF_LLVM_VERSION_MAJOR LLVM_VERSION_MAJOR
-#endif
-
 #if PYCLIF_LLVM_VERSION_MAJOR > 16
 #include "clang/Sema/EnterExpressionEvaluationContext.h"
 #endif
@@ -2989,20 +2985,20 @@ const clang::FunctionDecl* ClifMatcher::SpecializeFunctionTemplate(
 }
 
 std::string ClifMatcher::TemplateDeductionResult(
-    clang::TemplateDeductionResult specialized_result) const {
+    PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_TYPE specialized_result) const {
   switch (specialized_result) {
-    case clang::TemplateDeductionResult::Invalid:
+    case PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_ENUM(Invalid):
       return "The template function declaration was invalid.";
-    case clang::TemplateDeductionResult::InstantiationDepth:
+    case PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_ENUM(InstantiationDepth):
       return "Template argument deduction exceeded the maximum template "
              "instantiation depth.";
-    case clang::TemplateDeductionResult::Incomplete:
+    case PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_ENUM(Incomplete):
       return "Template argument deduction did not deduce a value for every "
              "template parameter.";
-    case clang::TemplateDeductionResult::Inconsistent:
+    case PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_ENUM(Inconsistent):
       return "Template argument deduction produced inconsistent deduced "
              "values.";
-    case clang::TemplateDeductionResult::Underqualified:
+    case PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_ENUM(Underqualified):
       return "Template argument deduction failed due to inconsistent "
              "cv-qualifiers.";
     default:
diff --git a/clif/backend/matcher.h b/clif/backend/matcher.h
index e30b2a5a..802f8a9a 100644
--- a/clif/backend/matcher.h
+++ b/clif/backend/matcher.h
@@ -48,6 +48,10 @@
 #include "clif/protos/ast.pb.h"
 #include "gtest/gtest_prod.h"  // Defines FRIEND_TEST.
 
+#ifndef PYCLIF_LLVM_VERSION_MAJOR
+#define PYCLIF_LLVM_VERSION_MAJOR LLVM_VERSION_MAJOR
+#endif
+
 namespace clif {
 
 // ############################################################################
@@ -177,6 +181,16 @@ enum TypeMatchFlags : unsigned int {
 class ClifError;
 class ClifMatcherTest;
 
+#if PYCLIF_LLVM_VERSION_MAJOR >= 19  // llvm/llvm-project#81398
+#define PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_TYPE clang::TemplateDeductionResult
+#define PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_ENUM(Name) \
+  clang::TemplateDeductionResult::Name
+#else
+#define PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_TYPE \
+  clang::Sema::TemplateDeductionResult
+#define PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_ENUM(Name) Sema::TDK_##Name
+#endif
+
 class ClifMatcher {
   friend class ClifMatcherTest;
  public:
@@ -402,7 +416,7 @@ class ClifMatcher {
 
   // Transform template type deduction error codes into error messages.
   std::string TemplateDeductionResult(
-      clang::TemplateDeductionResult specialized_result) const;
+      PYCLIF_CLANG_TEMPLATEDEDUCTIONRESULT_TYPE specialized_result) const;
 
   // Add the class type as the first parameter to a function.
   void AdjustForNonClassMethods(protos::FuncDecl* clif_func_decl) const;