diff --git a/test/ruby/test_backtrace.rb b/test/ruby/test_backtrace.rb
index 6ec13e4cc5..ed36fe95f6 100644
--- a/test/ruby/test_backtrace.rb
+++ b/test/ruby/test_backtrace.rb
@@ -214,4 +214,31 @@ class TestBacktrace < Test::Unit::TestCase
       q << true
     end
   end
+
+  def test_core_backtrace_alias
+    obj = BasicObject.new
+    e = assert_raise(NameError) do
+      class << obj
+        alias foo bar
+      end
+    end
+    assert_not_match(/\Acore#/, e.backtrace_locations[0].base_label)
+  end
+
+  def test_core_backtrace_undef
+    obj = BasicObject.new
+    e = assert_raise(NameError) do
+      class << obj
+        undef foo
+      end
+    end
+    assert_not_match(/\Acore#/, e.backtrace_locations[0].base_label)
+  end
+
+  def test_core_backtrace_hash_merge
+    e = assert_raise(TypeError) do
+      {**nil}
+    end
+    assert_not_match(/\Acore#/, e.backtrace_locations[0].base_label)
+  end
 end
diff --git a/version.h b/version.h
index fa85fbe3b2..cc54704b1b 100644
--- a/version.h
+++ b/version.h
@@ -1,10 +1,10 @@
 #define RUBY_VERSION "2.1.2"
-#define RUBY_RELEASE_DATE "2014-06-30"
-#define RUBY_PATCHLEVEL 157
+#define RUBY_RELEASE_DATE "2014-07-01"
+#define RUBY_PATCHLEVEL 158
 
 #define RUBY_RELEASE_YEAR 2014
-#define RUBY_RELEASE_MONTH 6
-#define RUBY_RELEASE_DAY 30
+#define RUBY_RELEASE_MONTH 7
+#define RUBY_RELEASE_DAY 1
 
 #include "ruby/version.h"
 
diff --git a/vm.c b/vm.c
index f74d4c485d..e8e2257e67 100644
--- a/vm.c
+++ b/vm.c
@@ -2262,46 +2262,62 @@ m_core_set_postexe(VALUE self)
     return Qnil;
 }
 
+static VALUE core_hash_merge_ary(VALUE hash, VALUE ary);
+static VALUE core_hash_from_ary(VALUE ary);
+static VALUE core_hash_merge_kwd(int argc, VALUE *argv);
+
+static VALUE
+core_hash_merge(VALUE hash, long argc, const VALUE *argv)
+{
+    long i;
+
+    assert(argc % 2 == 0);
+    for (i=0; i<argc; i+=2) {
+	rb_hash_aset(hash, argv[i], argv[i+1]);
+    }
+    return hash;
+}
+
 static VALUE
 m_core_hash_from_ary(VALUE self, VALUE ary)
+{
+    VALUE hash;
+    REWIND_CFP(hash = core_hash_from_ary(ary));
+    return hash;
+}
+
+static VALUE
+core_hash_from_ary(VALUE ary)
 {
     VALUE hash = rb_hash_new();
-    int i;
 
     if (RUBY_DTRACE_HASH_CREATE_ENABLED()) {
 	RUBY_DTRACE_HASH_CREATE(RARRAY_LEN(ary), rb_sourcefile(), rb_sourceline());
     }
 
-    assert(RARRAY_LEN(ary) % 2 == 0);
-    for (i=0; i<RARRAY_LEN(ary); i+=2) {
-	rb_hash_aset(hash, RARRAY_AREF(ary, i), RARRAY_AREF(ary, i+1));
-    }
-
-    return hash;
+    return core_hash_merge_ary(hash, ary);
 }
 
 static VALUE
 m_core_hash_merge_ary(VALUE self, VALUE hash, VALUE ary)
 {
-    int i;
-
-    assert(RARRAY_LEN(ary) % 2 == 0);
-    for (i=0; i<RARRAY_LEN(ary); i+=2) {
-	rb_hash_aset(hash, RARRAY_AREF(ary, i), RARRAY_AREF(ary, i+1));
-    }
+    REWIND_CFP(core_hash_merge_ary(hash, ary));
+    return hash;
+}
 
+static VALUE
+core_hash_merge_ary(VALUE hash, VALUE ary)
+{
+    core_hash_merge(hash, RARRAY_LEN(ary), RARRAY_CONST_PTR(ary));
     return hash;
 }
 
 static VALUE
 m_core_hash_merge_ptr(int argc, VALUE *argv, VALUE recv)
 {
-    int i;
     VALUE hash = argv[0];
 
-    for (i=1; i<argc; i+=2) {
-	rb_hash_aset(hash, argv[i], argv[i+1]);
-    }
+    REWIND_CFP(core_hash_merge(hash, argc-1, argv+1));
 
     return hash;
 }
@@ -2333,6 +2349,14 @@ kwcheck_i(VALUE key, VALUE value, VALUE hash)
 
 static VALUE
 m_core_hash_merge_kwd(int argc, VALUE *argv, VALUE recv)
+{
+    VALUE hash;
+    REWIND_CFP(hash = core_hash_merge_kwd(argc, argv));
+    return hash;
+}
+
+static VALUE
+core_hash_merge_kwd(int argc, VALUE *argv)
 {
     VALUE hash, kw;
     rb_check_arity(argc, 1, 2);