diff --git a/ChangeLog b/ChangeLog
index 6a38aa954a..6e9917c0d6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,21 @@
+Thu Sep 26 16:24:00 2013  Charlie Somerville  <charliesome@ruby-lang.org>
+
+	* insns.def (opt_regexpmatch1): check Regexp#=~ is not defined before
+	  calling rb_reg_match()
+
+	* test/ruby/test_regexp.rb: add test
+
+	* vm.c (ruby_vm_redefined_flag): change type to short[]
+
+	* vm.c (vm_redefinition_check_flag): return REGEXP_REDEFINED_OP_FLAG if
+	  klass == rb_cRegexp
+
+	* vm.c (vm_init_redefined_flag): setup BOP flag for Regexp#=~
+
+	* vm_insnhelper.h: add REGEXP_REDEFINED_OP_FLAG
+
+	[ruby-core:57385] [Bug #8953]
+
 Thu Sep 26 14:46:49 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* gc.c (mark_locations_array): disable AddressSanitizer.  based on a
diff --git a/insns.def b/insns.def
index 53e22223cd..a73501f245 100644
--- a/insns.def
+++ b/insns.def
@@ -2080,7 +2080,11 @@ opt_regexpmatch1
 (VALUE obj)
 (VALUE val)
 {
-    val = rb_reg_match(r, obj);
+    if (BASIC_OP_UNREDEFINED_P(BOP_MATCH, REGEXP_REDEFINED_OP_FLAG)) {
+	val = rb_reg_match(r, obj);
+    } else {
+	val = rb_funcall(r, idEqTilde, 1, obj);
+    }
 }
 
 /**
diff --git a/test/ruby/test_regexp.rb b/test/ruby/test_regexp.rb
index 7937fe8867..b8c08e38ca 100644
--- a/test/ruby/test_regexp.rb
+++ b/test/ruby/test_regexp.rb
@@ -1011,6 +1011,18 @@ class TestRegexp < Test::Unit::TestCase
     assert_equal(1, pr4.call(1))
   end
 
+  def test_eq_tilde_can_be_overridden
+    assert_in_out_err([], <<-RUBY, ["foo"], [])
+      class Regexp
+        def =~(str)
+          "foo"
+        end
+      end
+
+      puts // =~ ""
+    RUBY
+  end
+
   # This assertion is for porting x2() tests in testpy.py of Onigmo.
   def assert_match_at(re, str, positions, msg = nil)
     re = Regexp.new(re) unless re.is_a?(Regexp)
diff --git a/vm.c b/vm.c
index 3c50daa2fe..d647ab4a2a 100644
--- a/vm.c
+++ b/vm.c
@@ -99,7 +99,7 @@ VALUE rb_cEnv;
 VALUE rb_mRubyVMFrozenCore;
 
 VALUE ruby_vm_const_missing_count = 0;
-char ruby_vm_redefined_flag[BOP_LAST_];
+short ruby_vm_redefined_flag[BOP_LAST_];
 rb_thread_t *ruby_current_thread = 0;
 rb_vm_t *ruby_current_vm = 0;
 rb_event_flag_t ruby_vm_event_flags;
@@ -1016,6 +1016,7 @@ vm_redefinition_check_flag(VALUE klass)
     if (klass == rb_cBignum) return BIGNUM_REDEFINED_OP_FLAG;
     if (klass == rb_cSymbol) return SYMBOL_REDEFINED_OP_FLAG;
     if (klass == rb_cTime)   return TIME_REDEFINED_OP_FLAG;
+    if (klass == rb_cRegexp) return REGEXP_REDEFINED_OP_FLAG;
     return 0;
 }
 
@@ -1094,6 +1095,7 @@ vm_init_redefined_flag(void)
     OP(Size, SIZE), (C(Array), C(String), C(Hash));
     OP(EmptyP, EMPTY_P), (C(Array), C(String), C(Hash));
     OP(Succ, SUCC), (C(Fixnum), C(String), C(Time));
+    OP(EqTilde, MATCH), (C(Regexp));
 #undef C
 #undef OP
 }
diff --git a/vm_insnhelper.h b/vm_insnhelper.h
index 220404cfb5..73e88e5a42 100644
--- a/vm_insnhelper.h
+++ b/vm_insnhelper.h
@@ -55,11 +55,12 @@ enum {
   BOP_GE,
   BOP_NOT,
   BOP_NEQ,
+  BOP_MATCH,
 
   BOP_LAST_
 };
 
-extern char ruby_vm_redefined_flag[BOP_LAST_];
+extern short ruby_vm_redefined_flag[BOP_LAST_];
 extern VALUE ruby_vm_const_missing_count;
 
 #if VM_COLLECT_USAGE_DETAILS
@@ -237,6 +238,7 @@ enum vm_regan_acttype {
 #define BIGNUM_REDEFINED_OP_FLAG (1 << 5)
 #define SYMBOL_REDEFINED_OP_FLAG (1 << 6)
 #define TIME_REDEFINED_OP_FLAG   (1 << 7)
+#define REGEXP_REDEFINED_OP_FLAG (1 << 8)
 
 #define BASIC_OP_UNREDEFINED_P(op, klass) (LIKELY((ruby_vm_redefined_flag[(op)]&(klass)) == 0))