From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1778) id 5ECDC385C8B1; Mon, 3 Oct 2022 21:51:19 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 5ECDC385C8B1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1664833879; bh=eQMk7LZrcMW2O95iU07Bb/05xxi8qACf5lajnlqFADU=; h=From:To:Subject:Date:From; b=HLoPnRYKlUgcsCWbT4nxJtmTyW3ut3DMQ+7m7azctDKoz25EypPn0xfU+jK3AHxYw 1286cljgXsLJ4GdUZCg9FQeD/SP9ZNZzwWiS4bLKL7sXPixEnEIbHuqmehY2qd+X8l rWZsVVmPDoseWoiLqA7sDBipNO7fMz2cRZRccmLo= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Aurelien Jarno To: glibc-cvs@sourceware.org Subject: [glibc/release/2.36/master] x86-64: Require BMI2 for AVX2 wcs(n)cmp implementations X-Act-Checkin: glibc X-Git-Author: Aurelien Jarno X-Git-Refname: refs/heads/release/2.36/master X-Git-Oldrev: 29c577e0f54fe6e70ceacb3659179781c5569903 X-Git-Newrev: d8bf4388df679fa5a3ae7889a649e573e3124530 Message-Id: <20221003215119.5ECDC385C8B1@sourceware.org> Date: Mon, 3 Oct 2022 21:51:19 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=d8bf4388df679fa5a3ae7889a649e573e3124530 commit d8bf4388df679fa5a3ae7889a649e573e3124530 Author: Aurelien Jarno Date: Mon Oct 3 23:46:11 2022 +0200 x86-64: Require BMI2 for AVX2 wcs(n)cmp implementations The AVX2 wcs(n)cmp implementations use the 'bzhi' instruction, which belongs to the BMI2 CPU feature. NB: It also uses the 'tzcnt' BMI1 instruction, but it is executed as BSF as BSF if the CPU doesn't support TZCNT, and produces the same result for non-zero input. Partially fixes: b77b06e0e296 ("x86: Optimize strcmp-avx2.S") Partially resolves: BZ #29611 Reviewed-by: Noah Goldstein (cherry picked from commit f31a5a884ed84bd37032729d4d1eb9d06c9f3c29) Diff: --- sysdeps/x86_64/multiarch/ifunc-impl-list.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c index aebef3daaf..fec8790c11 100644 --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c @@ -810,10 +810,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, && CPU_FEATURE_USABLE (BMI2)), __wcscmp_evex) X86_IFUNC_IMPL_ADD_V3 (array, i, wcscmp, - CPU_FEATURE_USABLE (AVX2), + (CPU_FEATURE_USABLE (AVX2) + && CPU_FEATURE_USABLE (BMI2)), __wcscmp_avx2) X86_IFUNC_IMPL_ADD_V3 (array, i, wcscmp, (CPU_FEATURE_USABLE (AVX2) + && CPU_FEATURE_USABLE (BMI2) && CPU_FEATURE_USABLE (RTM)), __wcscmp_avx2_rtm) /* ISA V2 wrapper for SSE2 implementation because the SSE2 @@ -830,10 +832,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array, && CPU_FEATURE_USABLE (BMI2)), __wcsncmp_evex) X86_IFUNC_IMPL_ADD_V3 (array, i, wcsncmp, - CPU_FEATURE_USABLE (AVX2), + (CPU_FEATURE_USABLE (AVX2) + && CPU_FEATURE_USABLE (BMI2)), __wcsncmp_avx2) X86_IFUNC_IMPL_ADD_V3 (array, i, wcsncmp, (CPU_FEATURE_USABLE (AVX2) + && CPU_FEATURE_USABLE (BMI2) && CPU_FEATURE_USABLE (RTM)), __wcsncmp_avx2_rtm) /* ISA V2 wrapper for GENERIC implementation because the