Improve diagnostics from the assembler __memcpy_chk routines.

Change-Id: Iec16c92ed80beee505cba2121ea33e3550197b02
diff --git a/libc/arch-arm/denver/bionic/memcpy.S b/libc/arch-arm/denver/bionic/memcpy.S
index c1db06c..d4e0fb4 100644
--- a/libc/arch-arm/denver/bionic/memcpy.S
+++ b/libc/arch-arm/denver/bionic/memcpy.S
@@ -63,9 +63,14 @@
 
 ENTRY(__memcpy_chk)
         cmp     r2, r3
-        bhi     __memcpy_chk_fail
+        bls     memcpy
 
-        // Fall through to memcpy...
+        // Preserve lr for backtrace.
+        push    {lr}
+        .cfi_def_cfa_offset 4
+        .cfi_rel_offset lr, 0
+
+        bl      __memcpy_chk_fail
 END(__memcpy_chk)
 
 ENTRY(memcpy)
@@ -79,21 +84,3 @@
 #define MEMCPY_BASE         __memcpy_base
 #define MEMCPY_BASE_ALIGNED __memcpy_base_aligned
 #include "memcpy_base.S"
-
-ENTRY_PRIVATE(__memcpy_chk_fail)
-        // Preserve lr for backtrace.
-        push    {lr}
-        .cfi_def_cfa_offset 4
-        .cfi_rel_offset lr, 0
-
-        ldr     r0, error_message
-1:
-        add     r0, pc
-        bl      __fortify_fatal
-error_message:
-        .word   error_string-(1b+8)
-END(__memcpy_chk_fail)
-
-        .data
-error_string:
-        .string "memcpy: prevented write past end of buffer"