diff --git a/llvm/test/TableGen/lit.local.cfg b/llvm/test/TableGen/lit.local.cfg
--- a/llvm/test/TableGen/lit.local.cfg
+++ b/llvm/test/TableGen/lit.local.cfg
@@ -1,2 +1,3 @@
-config.suffixes = ['.td']
+config.suffixes = ['.td', '.test']
 config.excludes = ['Common']
+config.substitutions.append(('%llvm_lib_dir', f'{config.llvm_lib_dir}'))
diff --git a/llvm/test/TableGen/x86-fold-tables.td b/llvm/test/TableGen/x86-fold-tables.test
rename from llvm/test/TableGen/x86-fold-tables.td
rename to llvm/test/TableGen/x86-fold-tables.test
--- a/llvm/test/TableGen/x86-fold-tables.td
+++ b/llvm/test/TableGen/x86-fold-tables.test
@@ -3,5 +3,4 @@
 //      fix the vulnerable rules in X86FoldTablesEmitter.cpp until the diff is reasonable
 //   2. cp <generated_file> x86-fold-tables.inc
 
-// RUN: llvm-tblgen -gen-x86-fold-tables -asmwriternum=1 %p/../../lib/Target/X86/X86.td -I %p/../../lib/Target/X86 -I %p/../../include -o %t
-// RUN: diff %p/x86-fold-tables.inc %t
+// RUN: diff %p/x86-fold-tables.inc %llvm_lib_dir/Target/X86/X86GenFoldTables.inc