> Am 13.06.2022 um 16:36 schrieb H.J. Lu <hjl.to...@gmail.com>: > > On Mon, Jun 13, 2022 at 3:11 AM Richard Biener > <richard.guent...@gmail.com> wrote: >> >>> On Tue, Jun 7, 2022 at 9:02 PM H.J. Lu via Gcc-patches >>> <gcc-patches@gcc.gnu.org> wrote: >>> >>> Add -fextra-libc-function=memcmpeq 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= 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 <string.h> and GCC may generate > memcmp directly. How should we handle these cases? Not. Similar as to vectorized math functions. I think it’s not worth optimizing for this case. 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=. >>> * opts.cc (extra_libc_functions): New. >>> (parse_extra_libc_function): New function. >>> (common_handle_option): Handle -fextra-libc-function=. >>> * opts.h (extra_libc_function_list): New. >>> (extra_libc_functions): Likewise. >>> * doc/invoke.texi: Document -fextra-libc-function=memcmpeq. >>> >>> 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 subtarget, >>> machine_mode mode, >>> return target; >>> if (fcode == BUILT_IN_MEMCMP_EQ) >>> { >>> - tree newdecl = builtin_decl_explicit (BUILT_IN_MEMCMP); >>> + tree newdecl = builtin_decl_explicit >>> + (extra_libc_functions.has_memcmpeq >>> + ? BUILT_IN___MEMCMPEQ : BUILT_IN_MEMCMP); >>> TREE_OPERAND (exp, 1) = 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 with >>> + -fextra-libc-function=memcmpeq. */ >>> +DEF_EXT_LIB_BUILTIN (BUILT_IN___MEMCMPEQ, "__memcmpeq", >>> BT_FN_INT_CONST_PTR_CONST_PTR_SIZE, ATTR_PURE_NOTHROW_NONNULL_LEAF) >>> + >>> /* An internal version of strcmp/strncmp, used when the result is only >>> 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= >>> +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 C99/C11. >>> fpermitted-flt-eval-methods= >>> 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=memcmpeq @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 >>> supported by target machine. The >>> table is exact at each instruction boundary, so it can be used for stack >>> unwinding from asynchronous events (such as debugger or garbage collector). >>> >>> +@item -fextra-libc-function=memcmpeq >>> +@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= 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") == 0) >>> + { >>> + extra_libc_functions.has_memcmpeq = 1; >>> + return; >>> + } >>> + >>> + error ("unrecognized argument to %<-fextra-libc-function=%>: %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, value); >>> break; >>> >>> + case OPT_fextra_libc_function_: >>> + parse_extra_libc_function (arg); >>> + break; >>> + >>> case OPT_fprofile_generate_: >>> opts->x_profile_data_prefix = xstrdup (arg); >>> value = 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=memcmpeq" } */ >>> +/* { dg-final { scan-assembler "__memcmpeq" } } */ >>> + >>> +#include <stddef.h> >>> + >>> +int >>> +foo (const char *s1, const char *s2, size_t len) >>> +{ >>> + return __builtin_memcmp (s1, s2, len) != 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=memcmpeq" } */ >>> +/* { dg-final { scan-assembler "__memcmpeq" } } */ >>> + >>> +#include <string.h> >>> + >>> +int >>> +foo (const char *s1, const char *s2, size_t len) >>> +{ >>> + return memcmp (s1, s2, len) == 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=memcmpeq" } */ >>> +/* { dg-final { scan-assembler-not "__memcmpeq" } } */ >>> + >>> +#include <string.h> >>> + >>> +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 <stddef.h> >>> + >>> +int >>> +foo (const char *s1, const char *s2, size_t len) >>> +{ >>> + return __builtin_memcmp (s1, s2, len) != 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 <string.h> >>> + >>> +int >>> +foo (const char *s1, const char *s2, size_t len) >>> +{ >>> + return memcmp (s1, s2, len) == 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=memcmpeq" } */ >>> +/* { dg-final { scan-assembler "__memcmpeq" } } */ >>> + >>> +#include <stddef.h> >>> + >>> +int >>> +foo (const char *s1, const char *s2, size_t len) >>> +{ >>> + return __builtin_memcmp_eq (s1, s2, len) != 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 <stddef.h> >>> + >>> +int >>> +foo (const char *s1, const char *s2, size_t len) >>> +{ >>> + return __builtin_memcmp_eq (s1, s2, len) != 0; >>> +} >>> -- >>> 2.36.1 >>> > > > > -- > H.J.
Re: [PATCH] Add -fextra-libc-function=memcmpeq for __memcmpeq
Richard Biener via Gcc-patches Mon, 13 Jun 2022 09:01:29 -0700
- [PATCH] Add -fextra-libc-function=memcmpeq ... H.J. Lu via Gcc-patches
- Re: [PATCH] Add -fextra-libc-function=... Richard Biener via Gcc-patches
- Re: [PATCH] Add -fextra-libc-funct... H.J. Lu via Gcc-patches
- Re: [PATCH] Add -fextra-libc-f... Richard Biener via Gcc-patches
- Re: [PATCH] Add -fextra-li... H.J. Lu via Gcc-patches
- Re: [PATCH] Add -fext... Fangrui Song via Gcc-patches
- Re: [PATCH] Add -... Richard Biener via Gcc-patches
- Re: [PATCH] A... H.J. Lu via Gcc-patches