diff --git a/test_regress/Makefile b/test_regress/Makefile
index 78642a43c..55f572b68 100644
--- a/test_regress/Makefile
+++ b/test_regress/Makefile
@@ -73,6 +73,12 @@ random_forever:
 		echo ; \
 	done
 
+#######################################################################
+# Informational - used by some tests
+
+print-cxx-version:
+	$(CXX) --version
+
 ######################################################################
 maintainer-copy::
 clean mostlyclean distclean maintainer-clean::
diff --git a/test_regress/driver.pl b/test_regress/driver.pl
index 8ba9533ad..820838d63 100755
--- a/test_regress/driver.pl
+++ b/test_regress/driver.pl
@@ -1506,6 +1506,12 @@ sub _vcd_read {
     return $data;
 }
 
+our $_Cxx_Version;
+sub cxx_version {
+    $_Cxx_Version ||= `make -f Makefile print-cxx-version`;
+    return $_Cxx_Version;
+}
+
 sub file_grep_not {
     my $self = (ref $_[0]? shift : $Self);
     my $filename = shift;
diff --git a/test_regress/t/t_sys_sformat.v b/test_regress/t/t_sys_sformat.v
index 29ea527b0..7958425c3 100644
--- a/test_regress/t/t_sys_sformat.v
+++ b/test_regress/t/t_sys_sformat.v
@@ -56,11 +56,11 @@ module t;
       if (str2 !== "lib=t") $stop;
 
       str3 = $sformatf("u=%u", {"a","b","c","d"}); // Value selected so is printable
-`ifdef TEST_VERBOSE  $display("chku %0x %s",str3,str3);  `endif
+`ifdef TEST_VERBOSE  $display("chku %s %s",str3,str3);  `endif
       if (str3 !== "u=dcba") $stop;
 
       str3 = $sformatf("v=%v", {"a","b","c","d"}); // Value selected so is printable
-`ifdef TEST_VERBOSE  $display("chkv %0x %s",str3,str3);  `endif
+`ifdef TEST_VERBOSE  $display("chkv %s %s",str3,str3);  `endif
 
       $sformat(ochar,"%s","c");
       if (ochar != "c") $stop;
diff --git a/test_regress/t/t_sys_sformat_noopt.pl b/test_regress/t/t_sys_sformat_noopt.pl
index d069563a7..1d8758351 100755
--- a/test_regress/t/t_sys_sformat_noopt.pl
+++ b/test_regress/t/t_sys_sformat_noopt.pl
@@ -14,9 +14,14 @@ compile (
     verilator_flags2 => ["-O0"],
     );
 
-execute (
-	 check_finished=>1,
-     );
+if ($Self->cxx_version =~ /clang version 3.8/) {
+    $Self->skip("Known clang bug");
+    #Here:   if (VL_UNLIKELY(VL_NEQ_W(12, __Vtemp1, vlSymsp->TOP__t.__PVT__str)))
+} else{
+    execute (
+        check_finished=>1,
+        );
+}
 
 ok(1);
 1;