From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22259 invoked by alias); 21 Jun 2011 22:27:40 -0000 Received: (qmail 22249 invoked by uid 22791); 21 Jun 2011 22:27:38 -0000 X-SWARE-Spam-Status: No, hits=-6.8 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,TW_CX,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 21 Jun 2011 22:27:18 +0000 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p5LMRAGN031408 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 21 Jun 2011 18:27:10 -0400 Received: from [10.11.10.254] (vpn-10-254.rdu.redhat.com [10.11.10.254]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p5LMR9Rf016481; Tue, 21 Jun 2011 18:27:09 -0400 Message-ID: <4E011ABC.8070608@redhat.com> Date: Tue, 21 Jun 2011 23:03:00 -0000 From: Andrew MacLeod User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc13 Thunderbird/3.1.7 MIME-Version: 1.0 To: Richard Henderson CC: Aldy Hernandez , Jakub Jelinek , "Joseph S. Myers" , gcc-patches Subject: [cxx-mem-model] sync_mem_exchange implementation with memory model parameters References: <4DDAE516.4010307@redhat.com> <4DE3F8ED.6020109@redhat.com> <4DE7E0A6.9070400@redhat.com> <20110602192514.GA17079@tyan-ft48-01.lab.bos.redhat.com> <4DE7EA11.30306@redhat.com> <4DE8EF17.5020400@redhat.com> <4DFBC33E.60408@redhat.com> <4DFCFCE2.1090307@redhat.com> <4DFF73C1.6080609@redhat.com> <4DFFCAC6.7020206@redhat.com> <4DFFCF63.5040905@redhat.com> <4DFFD078.4090908@redhat.com> In-Reply-To: <4DFFD078.4090908@redhat.com> Content-Type: multipart/mixed; boundary="------------000705010400070505010700" X-IsSubscribed: yes Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2011-06/txt/msg01641.txt.bz2 This is a multi-part message in MIME format. --------------000705010400070505010700 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-length: 592 OK, I've brought the cxx-mem-model branch up to mainline as of this afternoon. (After I applied the patch which renamed all the mis-named _sync expanders) So this is the marginally reworked patch we had before which I think satisfies all the requests I've seen. Bootstraps and no regerssions on x86_64-unknown-linux-gnu. Assuming everyone is OK with this, I'll check it in and use it as a template for all the other __sync which need a memory model parameter specified at the end of http://gcc.gnu.org/wiki/Atomic/GCCMM/CodeGen Then I'll move on to the libstdc++ changes. Andrew --------------000705010400070505010700 Content-Type: text/plain; name="exchange.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="exchange.patch" Content-length: 17816 * doc/extend.texi (__sync_mem_exchange): Document. * cppbuiltin.c (define__GNUC__): Define __SYNC_MEM*. * c-family/c-common.c (BUILT_IN_SYNC_MEM_EXCHANGE_N): Add case. * optabs.c (expand_sync_mem_exchange): New. * optabs.h (enum direct_optab_index): Add DOI_sync_mem_exchange entry. (sync_mem_exchange_optab): Define. * genopinit.c: Add entry for sync_mem_exchange. * builtins.c (get_memmodel): New. (expand_builtin_sync_mem_exchange): New. (expand_builtin_sync_synchronize): Remove static. (expand_builtin): Add cases for BUILT_IN_SYNC_MEM_EXCHANGE_*. * sync-builtins.def: Add entries for BUILT_IN_SYNC_MEM_EXCHANGE_*. * testsuite/gcc.dg/x86-sync-1.c: New test. * builtin-types.def (BT_FN_I{1,2,4,8,16}_VPTR_I{1,2,4,8,16}_INT): New. * expr.h (expand_sync_mem_exchange): Declare. (expand_builtin_sync_synchronize): Declare. * fortran/types.def (BT_FN_I{1,2,4,8,16}_VPTR_I{1,2,4,8,16}_INT): New. * coretypes.h (enum memmodel): New. * Makefile.in (cppbuiltin.o) Add missing dependency on $(TREE_H) * config/i386/sync.md (sync_mem_exchange): New pattern. Index: doc/extend.texi =================================================================== *** doc/extend.texi (revision 175275) --- doc/extend.texi (working copy) *************** This builtin is not a full barrier, but *** 6728,6733 **** --- 6728,6751 ---- This means that all previous memory stores are globally visible, and all previous memory loads have been satisfied, but following memory reads are not prevented from being speculated to before the barrier. + + @item @var{type} __sync_mem_exchange (@var{type} *ptr, @var{type} value, int memmodel, ...) + @findex __sync_mem_exchange + This builtin implements an atomic exchange operation within the + constraints of a memory model. It writes @var{value} into + @code{*@var{ptr}}, and returns the previous contents of + @code{*@var{ptr}}. + + The valid memory model variants for this builtin are + __SYNC_MEM_RELAXED, __SYNC_MEM_SEQ_CST, __SYNC_MEM_ACQUIRE, + __SYNC_MEM_RELEASE, and __SYNC_MEM_ACQ_REL. The target pattern is responsible + for issuing the different synchronization instructions. It should default to + the more restrictive memory model, the sequentially consistent model. If + nothing is implemented for the target, the compiler will implement it by + calling the __sync_lock_test_and_set builtin. If the memory model is more + restrictive than memory_order_acquire, a memory barrier is emitted before + the instruction. + @end table @node Object Size Checking Index: cppbuiltin.c =================================================================== *** cppbuiltin.c (revision 175226) --- cppbuiltin.c (working copy) *************** define__GNUC__ (cpp_reader *pfile) *** 66,71 **** --- 66,77 ---- cpp_define_formatted (pfile, "__GNUC_MINOR__=%d", minor); cpp_define_formatted (pfile, "__GNUC_PATCHLEVEL__=%d", patchlevel); cpp_define_formatted (pfile, "__VERSION__=\"%s\"", version_string); + cpp_define_formatted (pfile, "__SYNC_MEM_RELAXED=%d", MEMMODEL_RELAXED); + cpp_define_formatted (pfile, "__SYNC_MEM_SEQ_CST=%d", MEMMODEL_SEQ_CST); + cpp_define_formatted (pfile, "__SYNC_MEM_ACQUIRE=%d", MEMMODEL_ACQUIRE); + cpp_define_formatted (pfile, "__SYNC_MEM_RELEASE=%d", MEMMODEL_RELEASE); + cpp_define_formatted (pfile, "__SYNC_MEM_ACQ_REL=%d", MEMMODEL_ACQ_REL); + cpp_define_formatted (pfile, "__SYNC_MEM_CONSUME=%d", MEMMODEL_CONSUME); } Index: c-family/c-common.c =================================================================== *** c-family/c-common.c (revision 175275) --- c-family/c-common.c (working copy) *************** resolve_overloaded_builtin (location_t l *** 9060,9065 **** --- 9060,9066 ---- case BUILT_IN_SYNC_VAL_COMPARE_AND_SWAP_N: case BUILT_IN_SYNC_LOCK_TEST_AND_SET_N: case BUILT_IN_SYNC_LOCK_RELEASE_N: + case BUILT_IN_SYNC_MEM_EXCHANGE_N: { int n = sync_resolve_size (function, params); tree new_function, first_param, result; Index: optabs.c =================================================================== *** optabs.c (revision 175275) --- optabs.c (working copy) *************** expand_sync_lock_test_and_set (rtx mem, *** 7056,7061 **** --- 7056,7101 ---- return NULL_RTX; } + + /* This function expands the atomic exchange operation: + atomically store VAL in MEM and return the previous value in MEM. + + MEMMODEL is the memory model variant to use. + TARGET is an option place to stick the return value. */ + + rtx + expand_sync_mem_exchange (enum memmodel model, rtx mem, rtx val, rtx target) + { + enum machine_mode mode = GET_MODE (mem); + enum insn_code icode; + + /* If the target supports the exchange directly, great. */ + icode = direct_optab_handler (sync_mem_exchange_optab, mode); + if (icode != CODE_FOR_nothing) + { + struct expand_operand ops[4]; + + create_output_operand (&ops[0], target, mode); + create_fixed_operand (&ops[1], mem); + /* VAL may have been promoted to a wider mode. Shrink it if so. */ + create_convert_operand_to (&ops[2], val, mode, true); + create_integer_operand (&ops[3], model); + if (maybe_expand_insn (icode, 4, ops)) + return ops[0].value; + } + + /* Legacy sync_lock_test_and_set works the same, but is only defined as an + acquire barrier. If the pattern exists, and the memory model is stronger + than acquire, add a release barrier before the instruction. + The barrier is not needed if sync_lock_test_and_set doesn't exist since + it will expand into a compare-and-swap loop. */ + icode = direct_optab_handler (sync_lock_test_and_set_optab, mode); + if ((icode != CODE_FOR_nothing) && (model == MEMMODEL_SEQ_CST || + model == MEMMODEL_ACQ_REL)) + expand_builtin_sync_synchronize (); + + return expand_sync_lock_test_and_set (mem, val, target); + } /* Return true if OPERAND is suitable for operand number OPNO of instruction ICODE. */ Index: optabs.h =================================================================== *** optabs.h (revision 175275) --- optabs.h (working copy) *************** enum direct_optab_index *** 677,682 **** --- 677,685 ---- /* Atomic clear with release semantics. */ DOI_sync_lock_release, + /* Atomic operations with C++0x memory model parameters. */ + DOI_sync_mem_exchange, + DOI_MAX }; *************** typedef struct direct_optab_d *direct_op *** 724,729 **** --- 727,735 ---- (&direct_optab_table[(int) DOI_sync_lock_test_and_set]) #define sync_lock_release_optab \ (&direct_optab_table[(int) DOI_sync_lock_release]) + + #define sync_mem_exchange_optab \ + (&direct_optab_table[(int) DOI_sync_mem_exchange]) /* Target-dependent globals. */ struct target_optabs { Index: genopinit.c =================================================================== *** genopinit.c (revision 175275) --- genopinit.c (working copy) *************** static const char * const optabs[] = *** 241,246 **** --- 241,247 ---- "set_direct_optab_handler (sync_compare_and_swap_optab, $A, CODE_FOR_$(sync_compare_and_swap$I$a$))", "set_direct_optab_handler (sync_lock_test_and_set_optab, $A, CODE_FOR_$(sync_lock_test_and_set$I$a$))", "set_direct_optab_handler (sync_lock_release_optab, $A, CODE_FOR_$(sync_lock_release$I$a$))", + "set_direct_optab_handler (sync_mem_exchange_optab, $A, CODE_FOR_$(sync_mem_exchange$I$a$))", "set_optab_handler (vec_set_optab, $A, CODE_FOR_$(vec_set$a$))", "set_optab_handler (vec_extract_optab, $A, CODE_FOR_$(vec_extract$a$))", "set_optab_handler (vec_extract_even_optab, $A, CODE_FOR_$(vec_extract_even$a$))", Index: builtins.c =================================================================== *** builtins.c (revision 175275) --- builtins.c (working copy) *************** expand_builtin_sync_lock_test_and_set (e *** 5199,5207 **** return expand_sync_lock_test_and_set (mem, val, target); } /* Expand the __sync_synchronize intrinsic. */ ! static void expand_builtin_sync_synchronize (void) { gimple x; --- 5199,5267 ---- return expand_sync_lock_test_and_set (mem, val, target); } + /* Given an integer representing an ``enum memmodel'', verify its + correctness and return the memory model enum. */ + + static enum memmodel + get_memmodel (tree exp) + { + rtx op; + + if (TREE_CODE (exp) != INTEGER_CST) + { + error ("third argument to builtin is an invalid memory model"); + return MEMMODEL_SEQ_CST; + } + op = expand_normal (exp); + if (INTVAL (op) < 0 || INTVAL (op) >= MEMMODEL_LAST) + { + error ("third argument to builtin is an invalid memory model"); + return MEMMODEL_SEQ_CST; + } + return (enum memmodel) INTVAL (op); + } + + /* Expand the __sync_mem_exchange intrinsic: + + TYPE __sync_mem_exchange (TYPE *to, TYPE from, enum memmodel) + + EXP is the CALL_EXPR. + TARGET is an optional place for us to store the results. */ + + static rtx + expand_builtin_sync_mem_exchange (enum machine_mode mode, tree exp, rtx target) + { + rtx val, mem; + enum machine_mode old_mode; + enum memmodel model; + + model = get_memmodel (CALL_EXPR_ARG (exp, 2)); + if (model != MEMMODEL_RELAXED + && model != MEMMODEL_SEQ_CST + && model != MEMMODEL_ACQ_REL + && model != MEMMODEL_RELEASE + && model != MEMMODEL_ACQUIRE) + { + error ("invalid memory model for %<__sync_mem_exchange%>"); + return NULL_RTX; + } + + /* Expand the operands. */ + mem = get_builtin_sync_mem (CALL_EXPR_ARG (exp, 0), mode); + val = expand_expr (CALL_EXPR_ARG (exp, 1), NULL_RTX, mode, EXPAND_NORMAL); + /* If VAL is promoted to a wider mode, convert it back to MODE. Take care + of CONST_INTs, where we know the old_mode only from the call argument. */ + old_mode = GET_MODE (val); + if (old_mode == VOIDmode) + old_mode = TYPE_MODE (TREE_TYPE (CALL_EXPR_ARG (exp, 1))); + val = convert_modes (mode, old_mode, val, 1); + + return expand_sync_mem_exchange (model, mem, val, target); + } + /* Expand the __sync_synchronize intrinsic. */ ! void expand_builtin_sync_synchronize (void) { gimple x; *************** expand_builtin (tree exp, rtx target, rt *** 6017,6022 **** --- 6077,6093 ---- return target; break; + case BUILT_IN_SYNC_MEM_EXCHANGE_1: + case BUILT_IN_SYNC_MEM_EXCHANGE_2: + case BUILT_IN_SYNC_MEM_EXCHANGE_4: + case BUILT_IN_SYNC_MEM_EXCHANGE_8: + case BUILT_IN_SYNC_MEM_EXCHANGE_16: + mode = get_builtin_sync_mode (fcode - BUILT_IN_SYNC_MEM_EXCHANGE_1); + target = expand_builtin_sync_mem_exchange (mode, exp, target); + if (target) + return target; + break; + case BUILT_IN_SYNC_LOCK_TEST_AND_SET_1: case BUILT_IN_SYNC_LOCK_TEST_AND_SET_2: case BUILT_IN_SYNC_LOCK_TEST_AND_SET_4: Index: sync-builtins.def =================================================================== *** sync-builtins.def (revision 175275) --- sync-builtins.def (working copy) *************** DEF_SYNC_BUILTIN (BUILT_IN_SYNC_LOCK_REL *** 256,258 **** --- 256,279 ---- DEF_SYNC_BUILTIN (BUILT_IN_SYNC_SYNCHRONIZE, "__sync_synchronize", BT_FN_VOID, ATTR_NOTHROW_LEAF_LIST) + + /* __sync* builtins for the C++ memory model. */ + + DEF_SYNC_BUILTIN (BUILT_IN_SYNC_MEM_EXCHANGE_N, + "__sync_mem_exchange", + BT_FN_VOID_VAR, ATTR_NOTHROW_LEAF_LIST) + DEF_SYNC_BUILTIN (BUILT_IN_SYNC_MEM_EXCHANGE_1, + "__sync_mem_exchange_1", + BT_FN_I1_VPTR_I1_INT, ATTR_NOTHROW_LEAF_LIST) + DEF_SYNC_BUILTIN (BUILT_IN_SYNC_MEM_EXCHANGE_2, + "__sync_mem_exchange_2", + BT_FN_I2_VPTR_I2_INT, ATTR_NOTHROW_LEAF_LIST) + DEF_SYNC_BUILTIN (BUILT_IN_SYNC_MEM_EXCHANGE_4, + "__sync_mem_exchange_4", + BT_FN_I4_VPTR_I4_INT, ATTR_NOTHROW_LEAF_LIST) + DEF_SYNC_BUILTIN (BUILT_IN_SYNC_MEM_EXCHANGE_8, + "__sync_mem_exchange_8", + BT_FN_I8_VPTR_I8_INT, ATTR_NOTHROW_LEAF_LIST) + DEF_SYNC_BUILTIN (BUILT_IN_SYNC_MEM_EXCHANGE_16, + "__sync_mem_exchange_16", + BT_FN_I16_VPTR_I16_INT, ATTR_NOTHROW_LEAF_LIST) Index: testsuite/gcc.dg/x86-sync-1.c =================================================================== *** testsuite/gcc.dg/x86-sync-1.c (revision 175275) --- testsuite/gcc.dg/x86-sync-1.c (working copy) *************** *** 0 **** --- 1,9 ---- + /* { dg-do compile } */ + /* { dg-options "-dap" } */ + + int i; + + void foo() + { + __sync_mem_exchange (&i, 555, __SYNC_MEM_SEQ_CST); + } Index: builtin-types.def =================================================================== *** builtin-types.def (revision 175226) --- builtin-types.def (working copy) *************** DEF_FUNCTION_TYPE_3 (BT_FN_VOID_OMPFN_PT *** 383,388 **** --- 383,393 ---- BT_PTR, BT_UINT) DEF_FUNCTION_TYPE_3 (BT_FN_PTR_CONST_PTR_INT_SIZE, BT_PTR, BT_CONST_PTR, BT_INT, BT_SIZE) + DEF_FUNCTION_TYPE_3 (BT_FN_I1_VPTR_I1_INT, BT_I1, BT_VOLATILE_PTR, BT_I1, BT_INT) + DEF_FUNCTION_TYPE_3 (BT_FN_I2_VPTR_I2_INT, BT_I2, BT_VOLATILE_PTR, BT_I2, BT_INT) + DEF_FUNCTION_TYPE_3 (BT_FN_I4_VPTR_I4_INT, BT_I4, BT_VOLATILE_PTR, BT_I4, BT_INT) + DEF_FUNCTION_TYPE_3 (BT_FN_I8_VPTR_I8_INT, BT_I8, BT_VOLATILE_PTR, BT_I8, BT_INT) + DEF_FUNCTION_TYPE_3 (BT_FN_I16_VPTR_I16_INT, BT_I16, BT_VOLATILE_PTR, BT_I16, BT_INT) DEF_FUNCTION_TYPE_4 (BT_FN_SIZE_CONST_PTR_SIZE_SIZE_FILEPTR, BT_SIZE, BT_CONST_PTR, BT_SIZE, BT_SIZE, BT_FILEPTR) Index: expr.h =================================================================== *** expr.h (revision 175229) --- expr.h (working copy) *************** rtx expand_bool_compare_and_swap (rtx, r *** 217,222 **** --- 217,223 ---- rtx expand_sync_operation (rtx, rtx, enum rtx_code); rtx expand_sync_fetch_operation (rtx, rtx, enum rtx_code, bool, rtx); rtx expand_sync_lock_test_and_set (rtx, rtx, rtx); + rtx expand_sync_mem_exchange (enum memmodel, rtx, rtx, rtx); /* Functions from expmed.c: */ *************** extern void expand_builtin_setjmp_receiv *** 248,253 **** --- 249,255 ---- extern rtx expand_builtin_saveregs (void); extern void expand_builtin_trap (void); extern rtx builtin_strncpy_read_str (void *, HOST_WIDE_INT, enum machine_mode); + extern void expand_builtin_sync_synchronize (void); /* Functions from expr.c: */ Index: fortran/types.def =================================================================== *** fortran/types.def (revision 175226) --- fortran/types.def (working copy) *************** DEF_FUNCTION_TYPE_3 (BT_FN_I16_VPTR_I16_ *** 120,125 **** --- 120,132 ---- DEF_FUNCTION_TYPE_3 (BT_FN_VOID_OMPFN_PTR_UINT, BT_VOID, BT_PTR_FN_VOID_PTR, BT_PTR, BT_UINT) + DEF_FUNCTION_TYPE_3 (BT_FN_I1_VPTR_I1_INT, BT_I1, BT_VOLATILE_PTR, BT_I1, BT_INT) + DEF_FUNCTION_TYPE_3 (BT_FN_I2_VPTR_I2_INT, BT_I2, BT_VOLATILE_PTR, BT_I2, BT_INT) + DEF_FUNCTION_TYPE_3 (BT_FN_I4_VPTR_I4_INT, BT_I4, BT_VOLATILE_PTR, BT_I4, BT_INT) + DEF_FUNCTION_TYPE_3 (BT_FN_I8_VPTR_I8_INT, BT_I8, BT_VOLATILE_PTR, BT_I8, BT_INT) + DEF_FUNCTION_TYPE_3 (BT_FN_I16_VPTR_I16_INT, BT_I16, BT_VOLATILE_PTR, BT_I16, BT_INT) + + DEF_FUNCTION_TYPE_4 (BT_FN_VOID_OMPFN_PTR_UINT_UINT, BT_VOID, BT_PTR_FN_VOID_PTR, BT_PTR, BT_UINT, BT_UINT) DEF_FUNCTION_TYPE_4 (BT_FN_VOID_PTR_WORD_WORD_PTR, Index: coretypes.h =================================================================== *** coretypes.h (revision 175226) --- coretypes.h (working copy) *************** union _dont_use_tree_here_; *** 171,175 **** --- 171,188 ---- #endif + /* Memory model types for the __sync_mem* builtins. + This must match the order in libstdc++-v3/include/bits/atomic_base.h. */ + enum memmodel + { + MEMMODEL_RELAXED = 0, + MEMMODEL_CONSUME = 1, + MEMMODEL_ACQUIRE = 2, + MEMMODEL_RELEASE = 3, + MEMMODEL_ACQ_REL = 4, + MEMMODEL_SEQ_CST = 5, + MEMMODEL_LAST = 6 + }; + #endif /* coretypes.h */ Index: Makefile.in =================================================================== *** Makefile.in (revision 175275) --- Makefile.in (working copy) *************** PREPROCESSOR_DEFINES = \ *** 4083,4089 **** @TARGET_SYSTEM_ROOT_DEFINE@ cppbuiltin.o: cppbuiltin.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \ ! cppbuiltin.h Makefile $(COMPILER) $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) \ $(PREPROCESSOR_DEFINES) -DBASEVER=$(BASEVER_s) \ -c $(srcdir)/cppbuiltin.c $(OUTPUT_OPTION) --- 4083,4089 ---- @TARGET_SYSTEM_ROOT_DEFINE@ cppbuiltin.o: cppbuiltin.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \ ! $(TREE_H) cppbuiltin.h Makefile $(COMPILER) $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) \ $(PREPROCESSOR_DEFINES) -DBASEVER=$(BASEVER_s) \ -c $(srcdir)/cppbuiltin.c $(OUTPUT_OPTION) Index: config/i386/sync.md =================================================================== *** config/i386/sync.md (revision 175229) --- config/i386/sync.md (working copy) *************** *** 232,237 **** --- 232,251 ---- return "lock{%;} add{}\t{%1, %0|%0, %1}"; }) + (define_expand "sync_mem_exchange" + [(match_operand:SWI 0 "register_operand" "") ;; output + (match_operand:SWI 1 "memory_operand" "") ;; memory + (match_operand:SWI 2 "register_operand" "") ;; input + (match_operand:SI 3 "const_int_operand" "")] ;; memory model + "" + { + /* On i386 the xchg instruction is a full barrier. Thus we + can completely ignore the memory model operand. */ + emit_insn (gen_sync_lock_test_and_set + (operands[0], operands[1], operands[2])); + DONE; + }) + ;; Recall that xchg implicitly sets LOCK#, so adding it again wastes space. (define_insn "sync_lock_test_and_set" [(set (match_operand:SWI 0 "register_operand" "=") --------------000705010400070505010700--