From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by sourceware.org (Postfix) with ESMTPS id 5265D3858288 for ; Wed, 15 Jun 2022 21:44:16 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 5265D3858288 Received: by mail-pj1-x102a.google.com with SMTP id g10-20020a17090a708a00b001ea8aadd42bso32302pjk.0 for ; Wed, 15 Jun 2022 14:44:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=eL8UV+DDhnuXvZm+pYta5cYSLKpz1VsZTvlPsRheAe0=; b=rUjhl3QcG1PM28ve4kQ5pJINxBBM7EZ0SkAsW0uzGPt9l+y3J00pnHK6N4dS0ybnFD 0Bh9QjcwlITGmGzEVyKy5qPzrx7XJkM0gJymbPLFHdTzE24L0amykT9+FcFM15wxgofa VYRNbe5oX5H+92zh8cZSoozbkpRx8/4BiaFG+/MbKeKfMHWJYVydY3rdT8XkLl0KHuUX VP6M1Cl16LVAqYTNwNXffgi56zSCETHLxCadkjvdanK8DKnsZHEQcbPufUXOKWxCHlfL XY3dzFUb2cMUplNlwGfMB7g2JBzP/PTGFlmy0bKted6G4TAqgGwEhI+l+n73ygmu8Tqr E8jg== X-Gm-Message-State: AJIora+54BVWq09JpuXLfC6zG99unNrFkpQPIDl0TA/pNgCEL83VgABe vJc46g5WtFEv8VcAGX0ltVmPFC2SmWwSYVge/Sc= X-Google-Smtp-Source: AGRyM1uhZl8YMoGzXYKl97hYkRwknOZg0MeAuNO6xH+axkmE839NgFCvf3u0c+qjnRZiycWZ72dZAw/TFsfwaCHVDEY= X-Received: by 2002:a17:90a:df16:b0:1e3:1cd:6c6f with SMTP id gp22-20020a17090adf1600b001e301cd6c6fmr12553812pjb.10.1655329455194; Wed, 15 Jun 2022 14:44:15 -0700 (PDT) MIME-Version: 1.0 References: <466A0F0B-DB25-4866-AB4B-27992CEF9E2E@gmail.com> In-Reply-To: <466A0F0B-DB25-4866-AB4B-27992CEF9E2E@gmail.com> From: "H.J. Lu" Date: Wed, 15 Jun 2022 14:43:39 -0700 Message-ID: Subject: Re: [PATCH] Add -fextra-libc-function=memcmpeq for __memcmpeq To: Richard Biener , Noah Goldstein Cc: "Joseph S. Myers" , GCC Patches Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-3025.4 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, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) 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: Wed, 15 Jun 2022 21:44:19 -0000 On Mon, Jun 13, 2022 at 9:01 AM Richard Biener wrote: > > > > > Am 13.06.2022 um 16:36 schrieb H.J. Lu : > > > > =EF=BB=BFOn Mon, Jun 13, 2022 at 3:11 AM Richard Biener > > wrote: > >> > >>> On Tue, Jun 7, 2022 at 9:02 PM H.J. Lu via Gcc-patches > >>> wrote: > >>> > >>> Add -fextra-libc-function=3Dmemcmpeq to map > >>> > >>> extern int __memcmpeq (const void *, const void *, size_t); > >>> > >>> which was added to GLIBC 2.35, to __builtin_memcmp_eq. > >> > >> Humm. Can't we instead use the presence of a declaration > >> of __memcmpeq with a GNU standard dialect as this instead of > >> adding a weird -fextra-libc-function=3D option? Maybe that's even > >> reasonable with a non-GNU dialect standard in effect since > >> __ prefixed names are in the implementation namespace? > > > > But not all source codes include and GCC may generate > > memcmp directly. How should we handle these cases? > > Not. Similar as to vectorized math functions. > I think it=E2=80=99s not worth optimizing for this case. Another question. Should we consider any __memcmpeq prototype or just the one in the system header file? > Richard. > > > > >> Richard. > >> > >>> gcc/ > >>> > >>> * builtins.cc: Include "opts.h". > >>> (expand_builtin): Generate BUILT_IN_MEMCMP_EQ if __memcmpeq is > >>> available. > >>> * builtins.def (BUILT_IN___MEMCMPEQ): New. > >>> * common.opt: Add -fextra-libc-function=3D. > >>> * opts.cc (extra_libc_functions): New. > >>> (parse_extra_libc_function): New function. > >>> (common_handle_option): Handle -fextra-libc-function=3D. > >>> * opts.h (extra_libc_function_list): New. > >>> (extra_libc_functions): Likewise. > >>> * doc/invoke.texi: Document -fextra-libc-function=3Dmemcmpeq. > >>> > >>> gcc/testsuite/ > >>> > >>> * c-c++-common/memcmpeq-1.c: New test. > >>> * c-c++-common/memcmpeq-2.c: Likewise. > >>> * c-c++-common/memcmpeq-3.c: Likewise. > >>> * c-c++-common/memcmpeq-4.c: Likewise. > >>> * c-c++-common/memcmpeq-5.c: Likewise. > >>> * c-c++-common/memcmpeq-6.c: Likewise. > >>> * c-c++-common/memcmpeq-7.c: Likewise. > >>> --- > >>> gcc/builtins.cc | 5 ++++- > >>> gcc/builtins.def | 4 ++++ > >>> gcc/common.opt | 4 ++++ > >>> gcc/doc/invoke.texi | 6 ++++++ > >>> gcc/opts.cc | 23 +++++++++++++++++++++++ > >>> gcc/opts.h | 7 +++++++ > >>> gcc/testsuite/c-c++-common/memcmpeq-1.c | 11 +++++++++++ > >>> gcc/testsuite/c-c++-common/memcmpeq-2.c | 11 +++++++++++ > >>> gcc/testsuite/c-c++-common/memcmpeq-3.c | 11 +++++++++++ > >>> gcc/testsuite/c-c++-common/memcmpeq-4.c | 11 +++++++++++ > >>> gcc/testsuite/c-c++-common/memcmpeq-5.c | 11 +++++++++++ > >>> gcc/testsuite/c-c++-common/memcmpeq-6.c | 11 +++++++++++ > >>> gcc/testsuite/c-c++-common/memcmpeq-7.c | 11 +++++++++++ > >>> 13 files changed, 125 insertions(+), 1 deletion(-) > >>> create mode 100644 gcc/testsuite/c-c++-common/memcmpeq-1.c > >>> create mode 100644 gcc/testsuite/c-c++-common/memcmpeq-2.c > >>> create mode 100644 gcc/testsuite/c-c++-common/memcmpeq-3.c > >>> create mode 100644 gcc/testsuite/c-c++-common/memcmpeq-4.c > >>> create mode 100644 gcc/testsuite/c-c++-common/memcmpeq-5.c > >>> create mode 100644 gcc/testsuite/c-c++-common/memcmpeq-6.c > >>> create mode 100644 gcc/testsuite/c-c++-common/memcmpeq-7.c > >>> > >>> diff --git a/gcc/builtins.cc b/gcc/builtins.cc > >>> index b9d89b409b8..22269318e8c 100644 > >>> --- a/gcc/builtins.cc > >>> +++ b/gcc/builtins.cc > >>> @@ -81,6 +81,7 @@ along with GCC; see the file COPYING3. If not see > >>> #include "demangle.h" > >>> #include "gimple-range.h" > >>> #include "pointer-query.h" > >>> +#include "opts.h" > >>> > >>> struct target_builtins default_target_builtins; > >>> #if SWITCHABLE_TARGET > >>> @@ -7410,7 +7411,9 @@ expand_builtin (tree exp, rtx target, rtx subta= rget, machine_mode mode, > >>> return target; > >>> if (fcode =3D=3D BUILT_IN_MEMCMP_EQ) > >>> { > >>> - tree newdecl =3D builtin_decl_explicit (BUILT_IN_MEMCMP); > >>> + tree newdecl =3D builtin_decl_explicit > >>> + (extra_libc_functions.has_memcmpeq > >>> + ? BUILT_IN___MEMCMPEQ : BUILT_IN_MEMCMP); > >>> TREE_OPERAND (exp, 1) =3D build_fold_addr_expr (newdecl); > >>> } > >>> break; > >>> diff --git a/gcc/builtins.def b/gcc/builtins.def > >>> index 005976f34e9..eb8d33b16e9 100644 > >>> --- a/gcc/builtins.def > >>> +++ b/gcc/builtins.def > >>> @@ -965,6 +965,10 @@ DEF_BUILTIN_STUB (BUILT_IN_ALLOCA_WITH_ALIGN_AND= _MAX, "__builtin_alloca_with_ali > >>> equality with zero. */ > >>> DEF_BUILTIN_STUB (BUILT_IN_MEMCMP_EQ, "__builtin_memcmp_eq") > >>> > >>> +/* Similar to BUILT_IN_MEMCMP_EQ, but is mapped to __memcmpeq only w= ith > >>> + -fextra-libc-function=3Dmemcmpeq. */ > >>> +DEF_EXT_LIB_BUILTIN (BUILT_IN___MEMCMPEQ, "__memcmpeq", BT_FN_INT_CO= NST_PTR_CONST_PTR_SIZE, ATTR_PURE_NOTHROW_NONNULL_LEAF) > >>> + > >>> /* An internal version of strcmp/strncmp, used when the result is onl= y > >>> tested for equality with zero. */ > >>> DEF_BUILTIN_STUB (BUILT_IN_STRCMP_EQ, "__builtin_strcmp_eq") > >>> diff --git a/gcc/common.opt b/gcc/common.opt > >>> index 7ca0cceed82..7a7631682b0 100644 > >>> --- a/gcc/common.opt > >>> +++ b/gcc/common.opt > >>> @@ -1587,6 +1587,10 @@ Enum(excess_precision) String(standard) Value(= EXCESS_PRECISION_STANDARD) > >>> EnumValue > >>> Enum(excess_precision) String(16) Value(EXCESS_PRECISION_FLOAT16) > >>> > >>> +fextra-libc-function=3D > >>> +Common Driver Joined > >>> +Specify the extra function in the C library. > >>> + > >>> ; Whether we permit the extended set of values for FLT_EVAL_METHOD > >>> ; introduced in ISO/IEC TS 18661-3, or limit ourselves to those in C9= 9/C11. > >>> fpermitted-flt-eval-methods=3D > >>> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi > >>> index 8cd5bdddc5d..fe1e3709953 100644 > >>> --- a/gcc/doc/invoke.texi > >>> +++ b/gcc/doc/invoke.texi > >>> @@ -676,6 +676,7 @@ Objective-C and Objective-C++ Dialects}. > >>> -ffixed-@var{reg} -fexceptions @gol > >>> -fnon-call-exceptions -fdelete-dead-exceptions -funwind-tables @gol > >>> -fasynchronous-unwind-tables @gol > >>> +-fextra-libc-function=3Dmemcmpeq @gol > >>> -fno-gnu-unique @gol > >>> -finhibit-size-directive -fcommon -fno-ident @gol > >>> -fpcc-struct-return -fpic -fPIC -fpie -fPIE -fno-plt @gol > >>> @@ -17250,6 +17251,11 @@ Generate unwind table in DWARF format, if su= pported by target machine. The > >>> table is exact at each instruction boundary, so it can be used for st= ack > >>> unwinding from asynchronous events (such as debugger or garbage colle= ctor). > >>> > >>> +@item -fextra-libc-function=3Dmemcmpeq > >>> +@opindex fextra-libc-function > >>> +Generate @code{__memcmpeq}, which was added to GLIBC 2.35, for > >>> +@code{__builtin_memcmp_eq}. > >>> + > >>> @item -fno-gnu-unique > >>> @opindex fno-gnu-unique > >>> @opindex fgnu-unique > >>> diff --git a/gcc/opts.cc b/gcc/opts.cc > >>> index bf06a55456a..e77f0922acc 100644 > >>> --- a/gcc/opts.cc > >>> +++ b/gcc/opts.cc > >>> @@ -38,6 +38,9 @@ along with GCC; see the file COPYING3. If not see > >>> /* In this file all option sets are explicit. */ > >>> #undef OPTION_SET_P > >>> > >>> +/* The list of extra functions in the C library. */ > >>> +extra_libc_function_list extra_libc_functions; > >>> + > >>> static void set_Wstrict_aliasing (struct gcc_options *opts, int onoff= ); > >>> > >>> /* Names of fundamental debug info formats indexed by enum > >>> @@ -2269,6 +2272,22 @@ parse_no_sanitize_attribute (char *value) > >>> return flags; > >>> } > >>> > >>> +/* Parse -fextra-libc-function=3D suboptions from ARG. */ > >>> + > >>> +static void > >>> +parse_extra_libc_function (const char *arg) > >>> +{ > >>> + /* Check to see if the string matches a sub-option name. */ > >>> + if (strcmp (arg, "memcmpeq") =3D=3D 0) > >>> + { > >>> + extra_libc_functions.has_memcmpeq =3D 1; > >>> + return; > >>> + } > >>> + > >>> + error ("unrecognized argument to %<-fextra-libc-function=3D%>: %qs= ", > >>> + arg); > >>> +} > >>> + > >>> /* Parse -fzero-call-used-regs suboptions from ARG, return the FLAGS.= */ > >>> > >>> unsigned int > >>> @@ -2940,6 +2959,10 @@ common_handle_option (struct gcc_options *opts= , > >>> SET_OPTION_IF_UNSET (opts, opts_set, flag_profile_correction, v= alue); > >>> break; > >>> > >>> + case OPT_fextra_libc_function_: > >>> + parse_extra_libc_function (arg); > >>> + break; > >>> + > >>> case OPT_fprofile_generate_: > >>> opts->x_profile_data_prefix =3D xstrdup (arg); > >>> value =3D true; > >>> diff --git a/gcc/opts.h b/gcc/opts.h > >>> index a43ce66cffe..e8d8835ba23 100644 > >>> --- a/gcc/opts.h > >>> +++ b/gcc/opts.h > >>> @@ -345,6 +345,13 @@ struct cl_option_handlers > >>> extern const char *opt_fstack_limit_symbol_arg; > >>> extern int opt_fstack_limit_register_no; > >>> > >>> +/* The list of extra functions in the C library. */ > >>> +struct extra_libc_function_list > >>> +{ > >>> + unsigned int has_memcmpeq : 1; > >>> +}; > >>> +extern extra_libc_function_list extra_libc_functions; > >>> + > >>> /* Input file names. */ > >>> > >>> extern const char **in_fnames; > >>> diff --git a/gcc/testsuite/c-c++-common/memcmpeq-1.c b/gcc/testsuite/= c-c++-common/memcmpeq-1.c > >>> new file mode 100644 > >>> index 00000000000..487f6cd98db > >>> --- /dev/null > >>> +++ b/gcc/testsuite/c-c++-common/memcmpeq-1.c > >>> @@ -0,0 +1,11 @@ > >>> +/* { dg-do compile } */ > >>> +/* { dg-options "-O2 -fextra-libc-function=3Dmemcmpeq" } */ > >>> +/* { dg-final { scan-assembler "__memcmpeq" } } */ > >>> + > >>> +#include > >>> + > >>> +int > >>> +foo (const char *s1, const char *s2, size_t len) > >>> +{ > >>> + return __builtin_memcmp (s1, s2, len) !=3D 0; > >>> +} > >>> diff --git a/gcc/testsuite/c-c++-common/memcmpeq-2.c b/gcc/testsuite/= c-c++-common/memcmpeq-2.c > >>> new file mode 100644 > >>> index 00000000000..1773dc2bee1 > >>> --- /dev/null > >>> +++ b/gcc/testsuite/c-c++-common/memcmpeq-2.c > >>> @@ -0,0 +1,11 @@ > >>> +/* { dg-do compile } */ > >>> +/* { dg-options "-O2 -fextra-libc-function=3Dmemcmpeq" } */ > >>> +/* { dg-final { scan-assembler "__memcmpeq" } } */ > >>> + > >>> +#include > >>> + > >>> +int > >>> +foo (const char *s1, const char *s2, size_t len) > >>> +{ > >>> + return memcmp (s1, s2, len) =3D=3D 0; > >>> +} > >>> diff --git a/gcc/testsuite/c-c++-common/memcmpeq-3.c b/gcc/testsuite/= c-c++-common/memcmpeq-3.c > >>> new file mode 100644 > >>> index 00000000000..69c9537d572 > >>> --- /dev/null > >>> +++ b/gcc/testsuite/c-c++-common/memcmpeq-3.c > >>> @@ -0,0 +1,11 @@ > >>> +/* { dg-do compile } */ > >>> +/* { dg-options "-O2 -fextra-libc-function=3Dmemcmpeq" } */ > >>> +/* { dg-final { scan-assembler-not "__memcmpeq" } } */ > >>> + > >>> +#include > >>> + > >>> +int > >>> +foo (const char *s1, const char *s2, size_t len) > >>> +{ > >>> + return memcmp (s1, s2, len); > >>> +} > >>> diff --git a/gcc/testsuite/c-c++-common/memcmpeq-4.c b/gcc/testsuite/= c-c++-common/memcmpeq-4.c > >>> new file mode 100644 > >>> index 00000000000..a448312ea96 > >>> --- /dev/null > >>> +++ b/gcc/testsuite/c-c++-common/memcmpeq-4.c > >>> @@ -0,0 +1,11 @@ > >>> +/* { dg-do compile } */ > >>> +/* { dg-options "-O2" } */ > >>> +/* { dg-final { scan-assembler-not "__memcmpeq" } } */ > >>> + > >>> +#include > >>> + > >>> +int > >>> +foo (const char *s1, const char *s2, size_t len) > >>> +{ > >>> + return __builtin_memcmp (s1, s2, len) !=3D 0; > >>> +} > >>> diff --git a/gcc/testsuite/c-c++-common/memcmpeq-5.c b/gcc/testsuite/= c-c++-common/memcmpeq-5.c > >>> new file mode 100644 > >>> index 00000000000..4ef33a1c238 > >>> --- /dev/null > >>> +++ b/gcc/testsuite/c-c++-common/memcmpeq-5.c > >>> @@ -0,0 +1,11 @@ > >>> +/* { dg-do compile } */ > >>> +/* { dg-options "-O2" } */ > >>> +/* { dg-final { scan-assembler-not "__memcmpeq" } } */ > >>> + > >>> +#include > >>> + > >>> +int > >>> +foo (const char *s1, const char *s2, size_t len) > >>> +{ > >>> + return memcmp (s1, s2, len) =3D=3D 0; > >>> +} > >>> diff --git a/gcc/testsuite/c-c++-common/memcmpeq-6.c b/gcc/testsuite/= c-c++-common/memcmpeq-6.c > >>> new file mode 100644 > >>> index 00000000000..52304df7079 > >>> --- /dev/null > >>> +++ b/gcc/testsuite/c-c++-common/memcmpeq-6.c > >>> @@ -0,0 +1,11 @@ > >>> +/* { dg-do compile } */ > >>> +/* { dg-options "-O2 -fextra-libc-function=3Dmemcmpeq" } */ > >>> +/* { dg-final { scan-assembler "__memcmpeq" } } */ > >>> + > >>> +#include > >>> + > >>> +int > >>> +foo (const char *s1, const char *s2, size_t len) > >>> +{ > >>> + return __builtin_memcmp_eq (s1, s2, len) !=3D 0; > >>> +} > >>> diff --git a/gcc/testsuite/c-c++-common/memcmpeq-7.c b/gcc/testsuite/= c-c++-common/memcmpeq-7.c > >>> new file mode 100644 > >>> index 00000000000..d59765894e7 > >>> --- /dev/null > >>> +++ b/gcc/testsuite/c-c++-common/memcmpeq-7.c > >>> @@ -0,0 +1,11 @@ > >>> +/* { dg-do compile } */ > >>> +/* { dg-options "-O2" } */ > >>> +/* { dg-final { scan-assembler-not "__memcmpeq" } } */ > >>> + > >>> +#include > >>> + > >>> +int > >>> +foo (const char *s1, const char *s2, size_t len) > >>> +{ > >>> + return __builtin_memcmp_eq (s1, s2, len) !=3D 0; > >>> +} > >>> -- > >>> 2.36.1 > >>> > > > > > > > > -- > > H.J. --=20 H.J.