diff --git a/libc/Android.bp b/libc/Android.bp
index 390cc0c..1fd8847 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -641,6 +641,7 @@
 // automatically included.
 cc_library_static {
     defaults: ["libc_defaults"],
+    tidy_disabled_srcs: ["upstream-*/**/*.c"],
     srcs: [
         // These two depend on getentropy, which isn't in libc_ndk.a.
         "upstream-openbsd/lib/libc/crypt/arc4random.c",
@@ -910,11 +911,14 @@
                 "arch-riscv64/bionic/syscall.S",
                 "arch-riscv64/bionic/vfork.S",
 
+                // TODO(b/306514350): Remove this and replace with the optimized
+                // version once the bug is resolved.
+                "upstream-freebsd/lib/libc/string/memcmp.c",
+
                 "bionic/strchrnul.cpp",
                 "bionic/strrchr.cpp",
 
                 "arch-riscv64/string/memchr.S",
-                "arch-riscv64/string/memcmp.S",
                 "arch-riscv64/string/memcpy.S",
                 "arch-riscv64/string/memmove.S",
                 "arch-riscv64/string/memset.S",
diff --git a/libc/arch-riscv64/string/memcmp.S b/libc/arch-riscv64/string/memcmp.S
deleted file mode 100644
index 9c1ecdc..0000000
--- a/libc/arch-riscv64/string/memcmp.S
+++ /dev/null
@@ -1,106 +0,0 @@
-/*
- * Copyright (C) 2023 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * 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.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "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
- * COPYRIGHT OWNER 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.
- */
-/*
- * Copyright (c) 2023 SiFive, Inc.
- * All rights reserved.
- *
- * 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 above 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. The name of the company may not be used to endorse or promote
- *    products derived from this software without specific prior written
- *    permission.
- *
- * THIS SOFTWARE IS PROVIDED BY SIFIVE INC ``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 SIFIVE INC 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.
- */
-
-#include <private/bionic_asm.h>
-
-#define iResult a0
-
-#define pSrc1 a0
-#define pSrc2 a1
-#define iNum a2
-
-#define iVL a3
-#define iTemp a4
-#define iTemp1 a5
-#define iTemp2 a6
-
-#define ELEM_LMUL_SETTING m8
-#define vData1 v0
-#define vData2 v8
-#define vMask v16
-
-ENTRY(memcmp)
-
-L(loop):
-    vsetvli iVL, iNum, e8, ELEM_LMUL_SETTING, ta, ma
-
-    vle8.v vData1, (pSrc1)
-    vle8.v vData2, (pSrc2)
-
-    vmsne.vv vMask, vData1, vData2
-    sub iNum, iNum, iVL
-    vfirst.m iTemp, vMask
-
-    /* skip the loop if we find the different
-       value between pSrc1 and pSrc2.  */
-    bgez iTemp, L(found)
-
-    add pSrc1, pSrc1, iVL
-    add pSrc2, pSrc2, iVL
-
-    bnez iNum, L(loop)
-
-    li iResult, 0
-    ret
-
-L(found):
-    add pSrc1, pSrc1, iTemp
-    add pSrc2, pSrc2, iTemp
-    lbu iTemp1, 0(pSrc1)
-    lbu iTemp2, 0(pSrc2)
-    sub iResult, iTemp1, iTemp2
-    ret
-
-END(memcmp)
diff --git a/libc/upstream-freebsd/lib/libc/string/memcmp.c b/libc/upstream-freebsd/lib/libc/string/memcmp.c
new file mode 100644
index 0000000..183b09c
--- /dev/null
+++ b/libc/upstream-freebsd/lib/libc/string/memcmp.c
@@ -0,0 +1,59 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * 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 above 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. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS 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.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)memcmp.c	8.1 (Berkeley) 6/4/93";
+#endif /* LIBC_SCCS and not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <string.h>
+
+/*
+ * Compare memory regions.
+ */
+int
+memcmp(const void *s1, const void *s2, size_t n)
+{
+	if (n != 0) {
+		const unsigned char *p1 = s1, *p2 = s2;
+
+		do {
+			if (*p1++ != *p2++)
+				return (*--p1 - *--p2);
+		} while (--n != 0);
+	}
+	return (0);
+}
+