[Bug target/106453] Redundant zero extension after crc32q
cvs-commit at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Mon Sep 5 18:02:22 GMT 2022
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106453
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Alexander Monakov <amonakov@gcc.gnu.org>:
https://gcc.gnu.org/g:810d9815249451f477d4cbc67b8e4a0819c37faa
commit r13-2448-g810d9815249451f477d4cbc67b8e4a0819c37faa
Author: Alexander Monakov <amonakov@ispras.ru>
Date: Tue Aug 23 18:42:24 2022 +0300
i386: avoid zero extension for crc32q
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.
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