diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 76c8fbfa494..31f01a07968 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2015-03-26  Jon Turney  <jon.turney@dronecode.org.uk>
+
+	* lib/gdb.exp (gdb_target_symbol_prefix_flags): Don't set
+	SYMBOL_PREFIX for x86_64-*-cygwin.
+
 2015-03-26  Andy Wingo  <wingo@igalia.com>
 
 	PR symtab/18148
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index f274b64d1fc..0041adf7a64 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -4998,7 +4998,7 @@ proc core_find {binfile {deletefiles {}} {arg ""}} {
 # TODO: find out automatically if the target needs this.
 
 proc gdb_target_symbol_prefix_flags {} {
-    if { [istarget "*-*-cygwin*"] || [istarget "i?86-*-mingw*"]
+    if { [istarget "i?86-*-cygwin*"] || [istarget "i?86-*-mingw*"]
 	 || [istarget "*-*-msdosdjgpp*"] || [istarget "*-*-go32*"] } {
 	return "additional_flags=-DSYMBOL_PREFIX=\"_\""
     } else {