diff --git a/crypto/CMakeLists.txt b/crypto/CMakeLists.txt
index 35c2262..2e255b8 100644
--- a/crypto/CMakeLists.txt
+++ b/crypto/CMakeLists.txt
@@ -114,7 +114,6 @@
 
 	crypto_error.c
 	mem.c
-	mem_clear.c
 	thread.c
 	ex_data.c
 	ex_data_impl.c
diff --git a/crypto/cpu-x86-asm.pl b/crypto/cpu-x86-asm.pl
index 151493a..1ac7d84 100644
--- a/crypto/cpu-x86-asm.pl
+++ b/crypto/cpu-x86-asm.pl
@@ -321,40 +321,6 @@
 	}
 &function_end_B("OPENSSL_indirect_call");
 
-&function_begin_B("OPENSSL_cleanse");
-	&mov	("edx",&wparam(0));
-	&mov	("ecx",&wparam(1));
-	&xor	("eax","eax");
-	&cmp	("ecx",7);
-	&jae	(&label("lot"));
-	&cmp	("ecx",0);
-	&je	(&label("ret"));
-&set_label("little");
-	&mov	(&BP(0,"edx"),"al");
-	&sub	("ecx",1);
-	&lea	("edx",&DWP(1,"edx"));
-	&jnz	(&label("little"));
-&set_label("ret");
-	&ret	();
-
-&set_label("lot",16);
-	&test	("edx",3);
-	&jz	(&label("aligned"));
-	&mov	(&BP(0,"edx"),"al");
-	&lea	("ecx",&DWP(-1,"ecx"));
-	&lea	("edx",&DWP(1,"edx"));
-	&jmp	(&label("lot"));
-&set_label("aligned");
-	&mov	(&DWP(0,"edx"),"eax");
-	&lea	("ecx",&DWP(-4,"ecx"));
-	&test	("ecx",-4);
-	&lea	("edx",&DWP(4,"edx"));
-	&jnz	(&label("aligned"));
-	&cmp	("ecx",0);
-	&jne	(&label("little"));
-	&ret	();
-&function_end_B("OPENSSL_cleanse");
-
 &function_begin_B("OPENSSL_ia32_rdrand");
 	&mov	("ecx",8);
 &set_label("loop");
diff --git a/crypto/mem.c b/crypto/mem.c
index a5f639b..e9c035e 100644
--- a/crypto/mem.c
+++ b/crypto/mem.c
@@ -93,6 +93,19 @@
   return ret;
 }
 
+void OPENSSL_cleanse(void *ptr, size_t len) {
+  memset(ptr, 0, len);
+
+  /* As best as we can tell, this is sufficient to break any optimisations that
+     might try to eliminate "superfluous" memsets. If there's an easy way to
+     detect memset_s, it would be better to use that. */
+#if defined(OPENSSL_WINDOWS)
+  __asm;
+#else
+  __asm__ __volatile__("" : : "r"(ptr) : "memory");
+#endif
+}
+
 int CRYPTO_memcmp(const void *in_a, const void *in_b, size_t len) {
   size_t i;
   const uint8_t *a = in_a;
diff --git a/crypto/mem_clear.c b/crypto/mem_clear.c
deleted file mode 100644
index 2c46ffe..0000000
--- a/crypto/mem_clear.c
+++ /dev/null
@@ -1,69 +0,0 @@
-/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved.
- *
- * This package is an SSL implementation written
- * by Eric Young (eay@cryptsoft.com).
- * The implementation was written so as to conform with Netscapes SSL.
- *
- * This library is free for commercial and non-commercial use as long as
- * the following conditions are aheared to.  The following conditions
- * apply to all code found in this distribution, be it the RC4, RSA,
- * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
- * included with this distribution is covered by the same copyright terms
- * except that the holder is Tim Hudson (tjh@cryptsoft.com).
- *
- * Copyright remains Eric Young's, and as such any Copyright notices in
- * the code are not to be removed.
- * If this package is used in a product, Eric Young should be given attribution
- * as the author of the parts of the library used.
- * This can be in the form of a textual message at program startup or
- * in documentation (online or textual) provided with the package.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *    "This product includes cryptographic software written by
- *     Eric Young (eay@cryptsoft.com)"
- *    The word 'cryptographic' can be left out if the rouines from the library
- *    being used are not cryptographic related :-).
- * 4. If you include any Windows specific code (or a derivative thereof) from
- *    the apps directory (application code) you must include an acknowledgement:
- *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
- *
- * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * The licence and distribution terms for any publically available version or
- * derivative of this code cannot be changed.  i.e. this code cannot simply be
- * copied and put under another distribution licence
- * [including the GNU Public Licence.] */
-
-#include <openssl/mem.h>
-
-#include <string.h>
-
-
-#if !defined(OPENSSL_X86) || defined(OPENSSL_NO_ASM)
-
-/* OPENSSL_cleanse is given its own compilation unit in the hopes that the
- * compiler won't be able to optimise it away. */
-/* TODO(fork): this is fragile. Preferably we would be able to use memset_s
- * on platforms with it. */
-void OPENSSL_cleanse(void *ptr, size_t len) { memset(ptr, 0, len); }
-
-#endif