diff --git a/executable_semantics/testdata/lit.cfg.py b/executable_semantics/testdata/lit.cfg.py
index ad4ba539ab49..088dd25e8ac0 100644
--- a/executable_semantics/testdata/lit.cfg.py
+++ b/executable_semantics/testdata/lit.cfg.py
@@ -35,5 +35,8 @@ config.substitutions.append(
 )
 config.substitutions.append(("%{not}", fullpath("llvm-project/llvm/not")))
 config.substitutions.append(
-    ("%{FileCheck}", fullpath("llvm-project/llvm/FileCheck"))
+    (
+        "%{FileCheck}",
+        fullpath("llvm-project/llvm/FileCheck --dump-input-filter=all"),
+    )
 )
diff --git a/toolchain/driver/testdata/lit.cfg.py b/toolchain/driver/testdata/lit.cfg.py
index 47c48bd43242..e975c265d658 100644
--- a/toolchain/driver/testdata/lit.cfg.py
+++ b/toolchain/driver/testdata/lit.cfg.py
@@ -28,5 +28,8 @@ config.substitutions.append(
 )
 config.substitutions.append(("%{not}", fullpath("llvm-project/llvm/not")))
 config.substitutions.append(
-    ("%{FileCheck}", fullpath("llvm-project/llvm/FileCheck"))
+    (
+        "%{FileCheck}",
+        fullpath("llvm-project/llvm/FileCheck --dump-input-filter=all"),
+    )
 )