diff --git a/clang.spec b/clang.spec
index 9bc65c1..d569d19 100644
--- a/clang.spec
+++ b/clang.spec
@@ -80,7 +80,7 @@
 
 Name:		%pkg_name
 Version:	%{clang_version}%{?rc_ver:~rc%{rc_ver}}%{?llvm_snapshot_version_suffix:~%{llvm_snapshot_version_suffix}}
-Release:	4%{?dist}
+Release:	5%{?dist}
 Summary:	A C language family front-end for LLVM
 
 License:	NCSA
@@ -559,7 +559,9 @@ echo "%%clang%{maj_ver}_resource_dir %%{_prefix}/lib/clang/%{maj_ver}" >> %{buil
 %cmake_build --target clang-test-depends \
     ExtraToolsUnitTests ClangdUnitTests ClangIncludeCleanerUnitTests ClangPseudoUnitTests
 # requires lit.py from LLVM utilities
-LD_LIBRARY_PATH=%{buildroot}/%{install_libdir} %{__ninja} %{_smp_mflags} check-all -C %{_vpath_builddir}
+# Set SOURCE_DATE_EPOCH to disable hardware acceleration on s390x
+# See https://bugzilla.redhat.com/show_bug.cgi?id=1994082
+SOURCE_DATE_EPOCH=1629181597 LD_LIBRARY_PATH=%{buildroot}/%{install_libdir} %{__ninja} %{_smp_mflags} check-all -C %{_vpath_builddir}
 %endif
 
 
@@ -730,6 +732,9 @@ LD_LIBRARY_PATH=%{buildroot}/%{install_libdir} %{__ninja} %{_smp_mflags} check-a
 
 %endif
 %changelog
+* Sat May 25 2024 Tom Stellard <tstellar@redhat.com> - 18.1.2-5
+- Set SOURCE_DATE_EPOCH when testing
+
 * Fri May 24 2024 Tom Stellard <tstellar@redhat.com> - 18.1.2-4
 - Limit number of compile jobs to avoid running out of memory