diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7a7b194ff84b..9ecf6511822e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -56,11 +56,10 @@ mark_as_advanced(Halide_CCACHE_BUILD)
 if (Halide_CCACHE_BUILD)
     find_program(CCACHE_PROGRAM ccache REQUIRED)
 
-    # TODO: ccache recommends setting CCACHE_SLOPPINESS=pch_defines,time_macros to
-    # enable precompiled header caching. Our timing found it slightly faster with
-    # just CCACHE_SLOPPINESS=pch_defines, so that's what we're using. Maybe revisit
-    # if issues occur (but we don't use any of the time macros so should be irrelevant).
-    set(Halide_CCACHE_PARAMS CCACHE_CPP2=yes CCACHE_HASHDIR=yes CCACHE_SLOPPINESS=pch_defines
+    set(Halide_CCACHE_PARAMS
+        CCACHE_CPP2=yes
+        CCACHE_HASHDIR=yes
+        CCACHE_SLOPPINESS=pch_defines,time_macros,include_file_mtime,include_file_ctime
         CACHE STRING "Parameters to pass through to ccache")
     mark_as_advanced(Halide_CCACHE_PARAMS)
 
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 78501a55c541..c64f47cff05e 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -7,6 +7,13 @@ add_executable(_test_internal internal.cpp)
 target_link_libraries(_test_internal PRIVATE Halide::Test)
 target_include_directories(_test_internal PRIVATE "${Halide_SOURCE_DIR}/src")
 target_precompile_headers(_test_internal PRIVATE <Halide.h>)
+if (Halide_CCACHE_BUILD)
+    if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+        target_compile_options(_test_internal PRIVATE
+            "$<$<COMPILE_LANGUAGE:CXX>:SHELL:-Xclang -fno-pch-timestamp>"
+        )
+    endif()
+endif()
 
 add_halide_test(_test_internal GROUPS internal)