diff --git a/test/hotspot/gtest/code/test_codestrings.cpp b/test/hotspot/gtest/code/test_codestrings.cpp
index fb45c36c5f2..550c3cc07c8 100644
--- a/test/hotspot/gtest/code/test_codestrings.cpp
+++ b/test/hotspot/gtest/code/test_codestrings.cpp
@@ -37,10 +37,13 @@ static const char* replace_addr_expr(const char* str)
 {
     // Remove any address expression "0x0123456789abcdef" found in order to
     // aid string comparison. Also remove any trailing printout from a padded
-    // buffer.
+    // buffer (too brittle?).
 
-    std::basic_string<char> tmp = std::regex_replace(str, std::regex("0x[0-9a-fA-F]+"), "<addr>");
-    std::basic_string<char> red = std::regex_replace(tmp, std::regex("\\s+<addr>:\\s+\\.inst\\t<addr> ; undefined"), "");
+    std::basic_string<char> tmp1 = std::regex_replace(str, std::regex("0x[0-9a-fA-F]+"), "<addr>");
+    // Padding: aarch64
+    std::basic_string<char> tmp2 = std::regex_replace(tmp1, std::regex("\\s+<addr>:\\s+\\.inst\\t<addr> ; undefined"), "");
+    // Padding: x64
+    std::basic_string<char> red  = std::regex_replace(tmp2, std::regex("\\s+<addr>:\\s+hlt[ \\t]+(?!\\n\\s+;;)"), "");
 
     return os::strdup(red.c_str());
 }