[PATCH] cksum: update to pclmul optimized crc32b from gnulib

[Pádraig Brady]

* bootstrap.conf: Depend on crc-x86_64 rather than crc.
* gnulib: Update to latest.
* src/cksum.c (crc32b_sum_stream): Add --debug info.
* NEWS: Mention the performance improvement.
---
 NEWS           | 1 +
 bootstrap.conf | 2 +-
 gnulib         | 2 +-
 src/cksum.c    | 7 ++++++-
 4 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/NEWS b/NEWS
index ed8754693..332e862d6 100644
--- a/NEWS
+++ b/NEWS
@@ -54,6 +54,7 @@ GNU coreutils NEWS                                    -*- 
outline -*-
 
   cksum -a now supports the "crc32b" option, which calculates the CRC
   of the input as defined by ITU V.42, as used by gzip for example.
+  For performance pclmul instructions are used where supported.
 
   ls now supports the --sort=name option,
   to explicitly select the default operation of sorting by file name.
diff --git a/bootstrap.conf b/bootstrap.conf
index 480e02931..e10c1ac54 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -64,7 +64,7 @@ gnulib_modules="
   config-h
   configmake
   copy-file-range
-  crc
+  crc-x86_64
   crypto/md5
   crypto/sha1
   crypto/sha256
diff --git a/gnulib b/gnulib
index 1f36fee69..da6b90f1f 160000
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 1f36fee699926dbd04d4b97ca19fad29a847c3ae
+Subproject commit da6b90f1fd041c013b9685ec4256e16d75b83f5d
diff --git a/src/cksum.c b/src/cksum.c
index 489af7e52..2a3bc57a0 100644
--- a/src/cksum.c
+++ b/src/cksum.c
@@ -149,7 +149,7 @@ static bool
 pclmul_supported (void)
 {
   bool pclmul_enabled = false;
-# if USE_PCLMUL_CRC32
+# if USE_PCLMUL_CRC32 || GL_CRC_X86_64_PCLMUL
   pclmul_enabled = (0 < __builtin_cpu_supports ("pclmul")
                     && 0 < __builtin_cpu_supports ("avx"));
 
@@ -332,6 +332,11 @@ crc32b_sum_stream (FILE *stream, void *resstream, 
uintmax_t *reslen)
   if (!stream || !resstream || !reslen)
     return -1;
 
+#if GL_CRC_X86_64_PCLMUL
+  if (cksum_debug)
+    (void) pclmul_supported ();
+#endif
+
   while ((bytes_read = fread (buf, 1, BUFLEN, stream)) > 0)
     {
       if (len + bytes_read < len)
-- 
2.47.1