From: Alexander Monakov <amonakov@ispras.ru>
To: gcc-patches@gcc.gnu.org
Cc: Alexander Monakov <amonakov@ispras.ru>
Subject: [PATCH] i386: avoid zero extension for crc32q
Date: Tue, 23 Aug 2022 19:09:46 +0300 [thread overview]
Message-ID: <20220823160946.19927-1-amonakov@ispras.ru> (raw)
The crc32q instruction takes 64-bit operands, but ignores high 32 bits
of the destination operand, and zero-extends the result from 32 bits.
Let's model this in the RTL pattern to avoid zero-extension when the
_mm_crc32_u64 intrinsic is used with a 32-bit type.
PR target/106453
gcc/ChangeLog:
* config/i386/i386.md (sse4_2_crc32di): Model that only low 32
bits of operand 0 are consumed, and the result is zero-extended
to 64 bits.
gcc/testsuite/ChangeLog:
* gcc.target/i386/pr106453.c: New test.
---
gcc/config/i386/i386.md | 6 +++---
gcc/testsuite/gcc.target/i386/pr106453.c | 13 +++++++++++++
2 files changed, 16 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/pr106453.c
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 58fcc382f..b5760bb23 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -23823,10 +23823,10 @@
(define_insn "sse4_2_crc32di"
[(set (match_operand:DI 0 "register_operand" "=r")
- (unspec:DI
- [(match_operand:DI 1 "register_operand" "0")
+ (zero_extend:DI (unspec:SI
+ [(match_operand:SI 1 "register_operand" "0")
(match_operand:DI 2 "nonimmediate_operand" "rm")]
- UNSPEC_CRC32))]
+ UNSPEC_CRC32)))]
"TARGET_64BIT && TARGET_CRC32"
"crc32{q}\t{%2, %0|%0, %2}"
[(set_attr "type" "sselog1")
diff --git a/gcc/testsuite/gcc.target/i386/pr106453.c b/gcc/testsuite/gcc.target/i386/pr106453.c
new file mode 100644
index 000000000..bab5b1cb2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr106453.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-msse4.2 -O2 -fdump-rtl-final" } */
+/* { dg-final { scan-rtl-dump-not "zero_extendsidi" "final" } } */
+
+#include <immintrin.h>
+#include <stdint.h>
+
+uint32_t f(uint32_t c, uint64_t *p, size_t n)
+{
+ for (size_t i = 0; i < n; i++)
+ c = _mm_crc32_u64(c, p[i]);
+ return c;
+}
--
2.35.1
next reply other threads:[~2022-08-23 16:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-23 16:09 Alexander Monakov [this message]
2022-08-24 11:35 ` Alexander Monakov
2022-09-04 19:36 ` Uros Bizjak
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220823160946.19927-1-amonakov@ispras.ru \
--to=amonakov@ispras.ru \
--cc=gcc-patches@gcc.gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).