diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cpp
@@ -462,7 +462,11 @@
 #elif SANITIZER_GLIBC && defined(__x86_64__)
   // For aarch64 and x86-64, use an O(1) approach which requires relatively
   // precise ThreadDescriptorSize. g_tls_size was initialized in InitTlsSize.
+#  if SANITIZER_X32
+  asm("mov %%fs:8,%0" : "=r"(*addr));
+#  else
   asm("mov %%fs:16,%0" : "=r"(*addr));
+#  endif
   *size = g_tls_size;
   *addr -= *size;
   *addr += ThreadDescriptorSize();