From 67dbc60e8f5a839aaaf3b218744d026165ac1cdf Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Thu, 8 Jun 2023 09:01:59 +0200
Subject: [PATCH] bytevector-slice: optimize trivial case

* libguile/bytevectors.c (scm_bytevector_slice): Return the bytevector
directly if start==0 and count==len.
---
 libguile/bytevectors.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libguile/bytevectors.c b/libguile/bytevectors.c
index 6d9f6476d..6b14c7246 100644
--- a/libguile/bytevectors.c
+++ b/libguile/bytevectors.c
@@ -357,6 +357,9 @@ SCM_DEFINE (scm_bytevector_slice, "bytevector-slice", 2, 1, 0,
   else
     c_size = scm_to_size_t (size);
 
+  if (c_offset == 0 && c_size == SCM_BYTEVECTOR_LENGTH (bv))
+    return bv;
+
   if (INT_ADD_OVERFLOW (c_offset, c_size)
       || (c_offset + c_size > SCM_BYTEVECTOR_LENGTH (bv)))
     scm_out_of_range (FUNC_NAME, offset);