@@ -, +, @@ 
---
 sysdeps/x86_64/multiarch/memcpy-ssse3-back.S |   11 +++++++++++
 sysdeps/x86_64/multiarch/memcpy-ssse3.S      |   11 +++++++++++
 2 files changed, 22 insertions(+), 0 deletions(-)
--- a/sysdeps/x86_64/multiarch/memcpy-ssse3-back.S	
+++ a/sysdeps/x86_64/multiarch/memcpy-ssse3-back.S	
@@ -57,6 +57,17 @@ END (MEMCPY_CHK)
 #endif
 
 ENTRY (MEMCPY)
+#ifndef USE_AS_MEMMOVE
+	lea	(%rsi, %rdx), %r9
+	lea	(%rdi, %rdx), %r11
+	cmp	%r9, %rdi		/* dest start >= source end */
+	jae	L(nonoverlap)		/*  -> nonoverlapping */
+	cmp	%r11, %rsi		/* source start >= destination end */
+	jae	L(nonoverlap)		/*  -> nonoverlapping */
+	movb	$0, 0
+	L(nonoverlap):
+#endif
+
 	mov	%rdi, %rax
 #ifdef USE_AS_MEMPCPY
 	add	%rdx, %rax
--- a/sysdeps/x86_64/multiarch/memcpy-ssse3.S	
+++ a/sysdeps/x86_64/multiarch/memcpy-ssse3.S	
@@ -57,6 +57,17 @@ END (MEMCPY_CHK)
 #endif
 
 ENTRY (MEMCPY)
+#ifndef USE_AS_MEMMOVE
+	lea	(%rsi, %rdx), %r9
+	lea	(%rdi, %rdx), %r11
+	cmp	%r9, %rdi		/* dest start >= source end */
+	jae	L(nonoverlap)		/*  -> nonoverlapping */
+	cmp	%r11, %rsi		/* source start >= destination end */
+	jae	L(nonoverlap)		/*  -> nonoverlapping */
+	movb	$0, 0
+	L(nonoverlap):
+#endif
+
 	mov	%rdi, %rax
 #ifdef USE_AS_MEMPCPY
 	add	%rdx, %rax
--