From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ej1-x62a.google.com (mail-ej1-x62a.google.com [IPv6:2a00:1450:4864:20::62a]) by sourceware.org (Postfix) with ESMTPS id D2791385DC33 for ; Thu, 24 Jun 2021 12:35:12 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org D2791385DC33 Received: by mail-ej1-x62a.google.com with SMTP id gt18so9227238ejc.11 for ; Thu, 24 Jun 2021 05:35:12 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Emzig606mKFup8Rx+PkC66yIdRphgWIJxpBZ2pD1A/A=; b=uoJIkc1bHTJ+gz4KBqZST3QmvM7NMcKi62AxI79ENAvdPhHQXagtA4u3dQkQ2L540W SrQWvo3OwyamDHFgq8wgIGw+sdANB+gqJppPhSwme0yv3+pf083JUYQ47DSucRZZpCY4 H5i2v0o+5UdpW6ixC3J5cSBoOUbrqugEgCgf3J3B57iczkVduy59okVQo2hJqS/OsyxT y9ttTTm9O3Z/bqPXdPeGouHu5x8WbpfUf00rR5w/Umo9lpzD+29mhwteNV7hoNW6ze9x ALxrtKdAwMN7LcoEVTz4lNMqQhx0IBekz/ktMwvAE9uj+POwuC7fWuUSHJh28DLcs5Ug fS+w== X-Gm-Message-State: AOAM530vRphzLNfCDj2Z/WBifkRv1Zn4BXj8gcsJk3wLAdlJ3p/iODAJ Fl21S2jWjYytgiRiudcEbVMppT6bpbbV2AreTkPAIib4GH4= X-Google-Smtp-Source: ABdhPJw4ymeCfb0Ade6M1IUE0/dDfq0I5LS0adEpqYQnlUfXBqlDX3ec+HUcAoMTGPI3mFUGC0aW3PAZrLOJyKWXbu0= X-Received: by 2002:a17:906:3c44:: with SMTP id i4mr5106812ejg.371.1624538111769; Thu, 24 Jun 2021 05:35:11 -0700 (PDT) MIME-Version: 1.0 References: <20210624121213.3469943-1-hjl.tools@gmail.com> In-Reply-To: <20210624121213.3469943-1-hjl.tools@gmail.com> From: Richard Biener Date: Thu, 24 Jun 2021 14:35:01 +0200 Message-ID: Subject: Re: [PATCH] x86: Compile CPUID functions with -mgeneral-regs-only To: "H.J. Lu" Cc: GCC Patches , Hongtao Liu Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-9.0 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 Jun 2021 12:35:15 -0000 On Thu, Jun 24, 2021 at 2:13 PM H.J. Lu via Gcc-patches wrote: > > CPUID functions are used to detect CPU features. If vector ISAs > are enabled, compiler is free to use them in these functions. Add > __attribute__ ((target("general-regs-only"))) to CPUID functions > to avoid vector instructions. But there are GPR instructions not in x86_64, so shouldn't we use target("march=x86_64") or so? Note doing either will of course prevent inlining of those "inlines". So I'm not sure how much of a fix this is ... the error will almost always be visible in the caller as well. > gcc/ > > PR target/101185 > * config/i386/cpuid.h (__get_cpuid_max): Add > __attribute__ ((target("general-regs-only"))). > (__get_cpuid): Likewise. > (__get_cpuid_count): Likewise. > (__cpuidex): Likewise. > > gcc/testsuite/ > > PR target/101185 > * gcc.target/i386/avx512-check.h (check_osxsave): Add > __attribute__ ((target("general-regs-only"))). > (main): Likewise. > --- > gcc/config/i386/cpuid.h | 4 ++++ > gcc/testsuite/gcc.target/i386/avx512-check.h | 2 ++ > 2 files changed, 6 insertions(+) > > diff --git a/gcc/config/i386/cpuid.h b/gcc/config/i386/cpuid.h > index aebc17c6827..74881ee91e5 100644 > --- a/gcc/config/i386/cpuid.h > +++ b/gcc/config/i386/cpuid.h > @@ -243,6 +243,7 @@ > pointer is non-null, then first four bytes of the signature > (as found in ebx register) are returned in location pointed by sig. */ > > +__attribute__ ((target("general-regs-only"))) > static __inline unsigned int > __get_cpuid_max (unsigned int __ext, unsigned int *__sig) > { > @@ -298,6 +299,7 @@ __get_cpuid_max (unsigned int __ext, unsigned int *__sig) > supported and returns 1 for valid cpuid information or 0 for > unsupported cpuid leaf. All pointers are required to be non-null. */ > > +__attribute__ ((target("general-regs-only"))) > static __inline int > __get_cpuid (unsigned int __leaf, > unsigned int *__eax, unsigned int *__ebx, > @@ -315,6 +317,7 @@ __get_cpuid (unsigned int __leaf, > > /* Same as above, but sub-leaf can be specified. */ > > +__attribute__ ((target("general-regs-only"))) > static __inline int > __get_cpuid_count (unsigned int __leaf, unsigned int __subleaf, > unsigned int *__eax, unsigned int *__ebx, > @@ -330,6 +333,7 @@ __get_cpuid_count (unsigned int __leaf, unsigned int __subleaf, > return 1; > } > > +__attribute__ ((target("general-regs-only"))) > static __inline void > __cpuidex (int __cpuid_info[4], int __leaf, int __subleaf) > { > diff --git a/gcc/testsuite/gcc.target/i386/avx512-check.h b/gcc/testsuite/gcc.target/i386/avx512-check.h > index 0a377dba1d5..406faf8fe03 100644 > --- a/gcc/testsuite/gcc.target/i386/avx512-check.h > +++ b/gcc/testsuite/gcc.target/i386/avx512-check.h > @@ -25,6 +25,7 @@ do_test (void) > } > #endif > > +__attribute__ ((target("general-regs-only"))) > static int > check_osxsave (void) > { > @@ -34,6 +35,7 @@ check_osxsave (void) > return (ecx & bit_OSXSAVE) != 0; > } > > +__attribute__ ((target("general-regs-only"))) > int > main () > { > -- > 2.31.1 >