From patchwork Thu Apr 21 16:59:36 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aldy Hernandez X-Patchwork-Id: 92431 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) by ozlabs.org (Postfix) with SMTP id A117CB6F47 for ; Fri, 22 Apr 2011 03:19:09 +1000 (EST) Received: (qmail 2956 invoked by alias); 21 Apr 2011 17:19:06 -0000 Received: (qmail 2947 invoked by uid 22791); 21 Apr 2011 17:19:03 -0000 X-SWARE-Spam-Status: No, hits=-6.5 required=5.0 tests=AWL, BAYES_00, RCVD_IN_DNSWL_HI, SPF_HELO_PASS, 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; Thu, 21 Apr 2011 17:18:46 +0000 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p3LHIYH9032745 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 21 Apr 2011 13:18:46 -0400 Received: from houston.quesejoda.com (vpn-233-139.phx2.redhat.com [10.3.233.139]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p3LGxac5014389; Thu, 21 Apr 2011 12:59:37 -0400 Message-ID: <4DB06278.3080300@redhat.com> Date: Thu, 21 Apr 2011 11:59:36 -0500 From: Aldy Hernandez User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.15) Gecko/20110307 Fedora/3.1.9-0.39.b3pre.fc14 Lightning/1.0b3pre Thunderbird/3.1.9 MIME-Version: 1.0 To: Jason Merrill , Richard Henderson CC: gcc-patches , Jakub Jelinek Subject: [cxx-mem-model] contiguous bitfields race implementation Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Delivered-To: mailing list gcc-patches@gcc.gnu.org To refresh everyone's memory, here is the problem: struct { unsigned int a : 4; unsigned char b; unsigned int c: 6; } var; void seta(){ var.a = 12; } Stores into cannot touch , so we can't store with anything wider (e.g. a 32 bit store) that will touch . This problem can be seen on strictly aligned targets such as Arm, where we store the above sequence with a 32-bit store. Or on x86-64 with being volatile (PR48124). This patch fixes both problems, but only for the C++ memory model. This is NOT a generic fix PR48124, only a fix when using "--param allow-store-data-races=0". The gist of this patch is in max_field_size(), where we calculate the maximum number of bits we can store into. In doing this calculation I assume we can store into the padding without causing any races. So, padding between fields and at the end of the structure are included. Tested on x86-64 with "--param allow-store-data-races=0". How does this look? I'd like a review before committing to the branch. Aldy * Makefile.in (expr.o): Depend on PARAMS_H. * machmode.h (get_best_mode): Add argument. * fold-const.c (optimize_bit_field_compare): Add argument to get_best_mode. (fold_truthop): Same. * ifcvt.c (noce_emit_move_insn): Add argument to store_bit_field. * expr.c (emit_group_store): Same. (copy_blkmode_from_reg): Same. (write_complex_part): Same. (optimize_bitfield_assignment_op): Add argument. Add argument to get_best_mode. (max_field_size): New. (expand_assignment): Calculate maxbits and pass it down accordingly. (store_field): New argument. (expand_expr_real_2): New argument to store_field. Include params.h. * expr.h (store_bit_field): New argument. * stor-layout.c (get_best_mode): Restrict mode expansion by taking into account maxbits. * calls.c (store_unaligned_arguments_into_pseudos): New argument to store_bit_field. * expmed.c (store_bit_field_1): New argument. Use it. (store_bit_field): Same. (store_fixed_bit_field): Same. (store_split_bit_field): Same. (extract_bit_field_1): Pass new argument to get_best_mode. (extract_bit_field): Same. * stmt.c (store_bit_field): Pass new argument to store_bit_field. * tree.h (DECL_THREAD_VISIBLE_P): New. Index: machmode.h =================================================================== --- machmode.h (revision 170745) +++ machmode.h (working copy) @@ -248,7 +248,9 @@ extern enum machine_mode mode_for_vector /* Find the best mode to use to access a bit field. */ -extern enum machine_mode get_best_mode (int, int, unsigned int, +extern enum machine_mode get_best_mode (int, int, + unsigned HOST_WIDE_INT, + unsigned int, enum machine_mode, int); /* Determine alignment, 1<=result<=BIGGEST_ALIGNMENT. */ Index: tree.h =================================================================== --- tree.h (revision 170745) +++ tree.h (working copy) @@ -3102,6 +3102,10 @@ struct GTY(()) tree_parm_decl { #define DECL_THREAD_LOCAL_P(NODE) \ (VAR_DECL_CHECK (NODE)->decl_with_vis.tls_model >= TLS_MODEL_REAL) +/* Return true if a VAR_DECL is visible from another thread. */ +#define DECL_THREAD_VISIBLE_P(NODE) \ + (TREE_STATIC (NODE) && !DECL_THREAD_LOCAL_P (NODE)) + /* In a non-local VAR_DECL with static storage duration, true if the variable has an initialization priority. If false, the variable will be initialized at the DEFAULT_INIT_PRIORITY. */ Index: fold-const.c =================================================================== --- fold-const.c (revision 170745) +++ fold-const.c (working copy) @@ -3426,7 +3426,7 @@ optimize_bit_field_compare (location_t l && flag_strict_volatile_bitfields > 0) nmode = lmode; else - nmode = get_best_mode (lbitsize, lbitpos, + nmode = get_best_mode (lbitsize, lbitpos, 0, const_p ? TYPE_ALIGN (TREE_TYPE (linner)) : MIN (TYPE_ALIGN (TREE_TYPE (linner)), TYPE_ALIGN (TREE_TYPE (rinner))), @@ -5254,7 +5254,7 @@ fold_truthop (location_t loc, enum tree_ to be relative to a field of that size. */ first_bit = MIN (ll_bitpos, rl_bitpos); end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize); - lnmode = get_best_mode (end_bit - first_bit, first_bit, + lnmode = get_best_mode (end_bit - first_bit, first_bit, 0, TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode, volatilep); if (lnmode == VOIDmode) @@ -5319,7 +5319,7 @@ fold_truthop (location_t loc, enum tree_ first_bit = MIN (lr_bitpos, rr_bitpos); end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize); - rnmode = get_best_mode (end_bit - first_bit, first_bit, + rnmode = get_best_mode (end_bit - first_bit, first_bit, 0, TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode, volatilep); if (rnmode == VOIDmode) Index: ifcvt.c =================================================================== --- ifcvt.c (revision 170745) +++ ifcvt.c (working copy) @@ -879,7 +879,7 @@ noce_emit_move_insn (rtx x, rtx y) } gcc_assert (start < (MEM_P (op) ? BITS_PER_UNIT : BITS_PER_WORD)); - store_bit_field (op, size, start, GET_MODE (x), y); + store_bit_field (op, size, start, 0, GET_MODE (x), y); return; } @@ -933,7 +933,7 @@ noce_emit_move_insn (rtx x, rtx y) inner = XEXP (outer, 0); outmode = GET_MODE (outer); bitpos = SUBREG_BYTE (outer) * BITS_PER_UNIT; - store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos, outmode, y); + store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos, 0, outmode, y); } /* Return sequence of instructions generated by if conversion. This Index: expr.c =================================================================== --- expr.c (revision 170745) +++ expr.c (working copy) @@ -54,6 +54,7 @@ along with GCC; see the file COPYING3. #include "diagnostic.h" #include "ssaexpand.h" #include "target-globals.h" +#include "params.h" /* Decide whether a function's arguments should be processed from first to last or from last to first. @@ -142,7 +143,8 @@ static void store_constructor_field (rtx HOST_WIDE_INT, enum machine_mode, tree, tree, int, alias_set_type); static void store_constructor (tree, rtx, int, HOST_WIDE_INT); -static rtx store_field (rtx, HOST_WIDE_INT, HOST_WIDE_INT, enum machine_mode, +static rtx store_field (rtx, HOST_WIDE_INT, HOST_WIDE_INT, + unsigned HOST_WIDE_INT, enum machine_mode, tree, tree, alias_set_type, bool); static unsigned HOST_WIDE_INT highest_pow2_factor_for_target (const_tree, const_tree); @@ -2077,7 +2079,7 @@ emit_group_store (rtx orig_dst, rtx src, emit_move_insn (adjust_address (dest, mode, bytepos), tmps[i]); else store_bit_field (dest, bytelen * BITS_PER_UNIT, bytepos * BITS_PER_UNIT, - mode, tmps[i]); + 0, mode, tmps[i]); } /* Copy from the pseudo into the (probable) hard reg. */ @@ -2171,7 +2173,7 @@ copy_blkmode_from_reg (rtx tgtblk, rtx s /* Use xbitpos for the source extraction (right justified) and bitpos for the destination store (left justified). */ - store_bit_field (dst, bitsize, bitpos % BITS_PER_WORD, copy_mode, + store_bit_field (dst, bitsize, bitpos % BITS_PER_WORD, 0, copy_mode, extract_bit_field (src, bitsize, xbitpos % BITS_PER_WORD, 1, false, NULL_RTX, copy_mode, copy_mode)); @@ -2830,7 +2832,7 @@ write_complex_part (rtx cplx, rtx val, b gcc_assert (MEM_P (cplx) && ibitsize < BITS_PER_WORD); } - store_bit_field (cplx, ibitsize, imag_p ? ibitsize : 0, imode, val); + store_bit_field (cplx, ibitsize, imag_p ? ibitsize : 0, 0, imode, val); } /* Extract one of the components of the complex value CPLX. Extract the @@ -3966,6 +3968,7 @@ get_subtarget (rtx x) static bool optimize_bitfield_assignment_op (unsigned HOST_WIDE_INT bitsize, unsigned HOST_WIDE_INT bitpos, + unsigned HOST_WIDE_INT maxbits, enum machine_mode mode1, rtx str_rtx, tree to, tree src) { @@ -4000,7 +4003,7 @@ optimize_bitfield_assignment_op (unsigne if (str_bitsize == 0 || str_bitsize > BITS_PER_WORD) str_mode = word_mode; - str_mode = get_best_mode (bitsize, bitpos, + str_mode = get_best_mode (bitsize, bitpos, maxbits, MEM_ALIGN (str_rtx), str_mode, 0); if (str_mode == VOIDmode) return false; @@ -4111,6 +4114,92 @@ optimize_bitfield_assignment_op (unsigne return false; } +/* In the C++ memory model, consecutive bit fields in a structure are + considered one memory location. + + Given a COMPONENT_REF, this function returns the maximum number of + bits we are allowed to store into, when storing into the + COMPONENT_REF. We return 0, if there is no restriction. + + EXP is the COMPONENT_REF. + + BITPOS is the position in bits where the bit starts within the structure. + BITSIZE is size in bits of the field being referenced in EXP. + + For example, while storing into FOO.A here... + + struct { + BIT 0: + unsigned int a : 4; + unsigned int b : 1; + BIT 8: + unsigned char c; + unsigned int d : 6; + } foo; + + ...we are not allowed to store past , so for the layout above, + we would return 8 maximum bits (because who cares if we store into + the padding). */ + + +static unsigned HOST_WIDE_INT +max_field_size (tree exp, HOST_WIDE_INT bitpos, HOST_WIDE_INT bitsize) +{ + tree field, record_type, fld; + HOST_WIDE_INT maxbits = bitsize; + + gcc_assert (TREE_CODE (exp) == COMPONENT_REF); + + /* If other threads can't see this value, no need to restrict stores. */ + if (ALLOW_STORE_DATA_RACES + || !DECL_THREAD_VISIBLE_P (TREE_OPERAND (exp, 0))) + return 0; + + field = TREE_OPERAND (exp, 1); + record_type = DECL_FIELD_CONTEXT (field); + + /* Find the original field within the structure. */ + for (fld = TYPE_FIELDS (record_type); fld; fld = DECL_CHAIN (fld)) + if (fld == field) + break; + gcc_assert (fld == field); + + /* If this is the last element in the structure, we can touch from + BITPOS to the end of the structure (including the padding). */ + if (!DECL_CHAIN (fld)) + return TREE_INT_CST_LOW (TYPE_SIZE (record_type)) - bitpos; + + /* Count contiguous bit fields not separated by a 0-length bit-field. */ + for (fld = DECL_CHAIN (fld); fld; fld = DECL_CHAIN (fld)) + { + tree t, offset; + enum machine_mode mode; + int unsignedp, volatilep; + + if (TREE_CODE (fld) != FIELD_DECL) + continue; + + t = build3 (COMPONENT_REF, TREE_TYPE (exp), + unshare_expr (TREE_OPERAND (exp, 0)), + fld, NULL_TREE); + get_inner_reference (t, &bitsize, &bitpos, &offset, + &mode, &unsignedp, &volatilep, true); + + /* Only count contiguous bit fields, that are not separated by a + zero-length bit field. */ + if (!DECL_BIT_FIELD (fld) + || bitsize == 0) + { + /* Include the padding up to the next field. */ + maxbits += bitpos - maxbits; + break; + } + + maxbits += bitsize; + } + + return maxbits; +} /* Expand an assignment that stores the value of FROM into TO. If NONTEMPORAL is true, try generating a nontemporal store. */ @@ -4213,6 +4302,9 @@ expand_assignment (tree to, tree from, b { enum machine_mode mode1; HOST_WIDE_INT bitsize, bitpos; + /* Max consecutive bits we are allowed to touch while storing + into TO. */ + HOST_WIDE_INT maxbits = 0; tree offset; int unsignedp; int volatilep = 0; @@ -4222,6 +4314,10 @@ expand_assignment (tree to, tree from, b tem = get_inner_reference (to, &bitsize, &bitpos, &offset, &mode1, &unsignedp, &volatilep, true); + if (TREE_CODE (to) == COMPONENT_REF + && DECL_BIT_FIELD (TREE_OPERAND (to, 1))) + maxbits = max_field_size (to, bitpos, bitsize); + /* If we are going to use store_bit_field and extract_bit_field, make sure to_rtx will be safe for multiple use. */ @@ -4322,11 +4418,12 @@ expand_assignment (tree to, tree from, b MEM_KEEP_ALIAS_SET_P (to_rtx) = 1; } - if (optimize_bitfield_assignment_op (bitsize, bitpos, mode1, + if (optimize_bitfield_assignment_op (bitsize, bitpos, maxbits, mode1, to_rtx, to, from)) result = NULL; else - result = store_field (to_rtx, bitsize, bitpos, mode1, from, + result = store_field (to_rtx, bitsize, bitpos, maxbits, + mode1, from, TREE_TYPE (tem), get_alias_set (to), nontemporal); } @@ -4734,7 +4831,7 @@ store_expr (tree exp, rtx target, int ca : BLOCK_OP_NORMAL)); else if (GET_MODE (target) == BLKmode) store_bit_field (target, INTVAL (expr_size (exp)) * BITS_PER_UNIT, - 0, GET_MODE (temp), temp); + 0, 0, GET_MODE (temp), temp); else convert_move (target, temp, unsignedp); } @@ -5177,7 +5274,8 @@ store_constructor_field (rtx target, uns store_constructor (exp, target, cleared, bitsize / BITS_PER_UNIT); } else - store_field (target, bitsize, bitpos, mode, exp, type, alias_set, false); + store_field (target, bitsize, bitpos, 0, mode, exp, type, alias_set, + false); } /* Store the value of constructor EXP into the rtx TARGET. @@ -5751,6 +5849,8 @@ store_constructor (tree exp, rtx target, BITSIZE bits, starting BITPOS bits from the start of TARGET. If MODE is VOIDmode, it means that we are storing into a bit-field. + MAXBITS is the number of bits we can store into, 0 if no limit. + Always return const0_rtx unless we have something particular to return. @@ -5764,6 +5864,7 @@ store_constructor (tree exp, rtx target, static rtx store_field (rtx target, HOST_WIDE_INT bitsize, HOST_WIDE_INT bitpos, + unsigned HOST_WIDE_INT maxbits, enum machine_mode mode, tree exp, tree type, alias_set_type alias_set, bool nontemporal) { @@ -5796,8 +5897,8 @@ store_field (rtx target, HOST_WIDE_INT b if (bitsize != (HOST_WIDE_INT) GET_MODE_BITSIZE (GET_MODE (target))) emit_move_insn (object, target); - store_field (blk_object, bitsize, bitpos, mode, exp, type, alias_set, - nontemporal); + store_field (blk_object, bitsize, bitpos, maxbits, + mode, exp, type, alias_set, nontemporal); emit_move_insn (target, object); @@ -5912,7 +6013,7 @@ store_field (rtx target, HOST_WIDE_INT b } /* Store the value in the bitfield. */ - store_bit_field (target, bitsize, bitpos, mode, temp); + store_bit_field (target, bitsize, bitpos, maxbits, mode, temp); return const0_rtx; } @@ -7323,7 +7424,7 @@ expand_expr_real_2 (sepops ops, rtx targ (treeop0)) * BITS_PER_UNIT), (HOST_WIDE_INT) GET_MODE_BITSIZE (mode)), - 0, TYPE_MODE (valtype), treeop0, + 0, 0, TYPE_MODE (valtype), treeop0, type, 0, false); } Index: expr.h =================================================================== --- expr.h (revision 170745) +++ expr.h (working copy) @@ -666,7 +666,8 @@ extern enum machine_mode mode_for_extraction (enum extraction_pattern, int); extern void store_bit_field (rtx, unsigned HOST_WIDE_INT, - unsigned HOST_WIDE_INT, enum machine_mode, rtx); + unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT, + enum machine_mode, rtx); extern rtx extract_bit_field (rtx, unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT, int, bool, rtx, enum machine_mode, enum machine_mode); Index: stor-layout.c =================================================================== --- stor-layout.c (revision 170745) +++ stor-layout.c (working copy) @@ -2432,6 +2432,9 @@ fixup_unsigned_type (tree type) /* Find the best machine mode to use when referencing a bit field of length BITSIZE bits starting at BITPOS. + MAXBITS is the maximum number of bits we are allowed to touch, when + referencing this bit field. MAXBITS is 0 if there is no limit. + The underlying object is known to be aligned to a boundary of ALIGN bits. If LARGEST_MODE is not VOIDmode, it means that we should not use a mode larger than LARGEST_MODE (usually SImode). @@ -2449,7 +2452,8 @@ fixup_unsigned_type (tree type) decide which of the above modes should be used. */ enum machine_mode -get_best_mode (int bitsize, int bitpos, unsigned int align, +get_best_mode (int bitsize, int bitpos, unsigned HOST_WIDE_INT maxbits, + unsigned int align, enum machine_mode largest_mode, int volatilep) { enum machine_mode mode; @@ -2488,6 +2492,7 @@ get_best_mode (int bitsize, int bitpos, if (bitpos / unit == (bitpos + bitsize - 1) / unit && unit <= BITS_PER_WORD && unit <= MIN (align, BIGGEST_ALIGNMENT) + && (!maxbits || unit <= maxbits) && (largest_mode == VOIDmode || unit <= GET_MODE_BITSIZE (largest_mode))) wide_mode = tmode; Index: calls.c =================================================================== --- calls.c (revision 170745) +++ calls.c (working copy) @@ -903,7 +903,7 @@ store_unaligned_arguments_into_pseudos ( emit_move_insn (reg, const0_rtx); bytes -= bitsize / BITS_PER_UNIT; - store_bit_field (reg, bitsize, endian_correction, word_mode, + store_bit_field (reg, bitsize, endian_correction, 0, word_mode, word); } } Index: expmed.c =================================================================== --- expmed.c (revision 170745) +++ expmed.c (working copy) @@ -47,9 +47,13 @@ struct target_expmed *this_target_expmed static void store_fixed_bit_field (rtx, unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT, - unsigned HOST_WIDE_INT, rtx); + unsigned HOST_WIDE_INT, + unsigned HOST_WIDE_INT, + rtx); static void store_split_bit_field (rtx, unsigned HOST_WIDE_INT, - unsigned HOST_WIDE_INT, rtx); + unsigned HOST_WIDE_INT, + unsigned HOST_WIDE_INT, + rtx); static rtx extract_fixed_bit_field (enum machine_mode, rtx, unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT, @@ -349,7 +353,9 @@ check_predicate_volatile_ok (enum insn_c static bool store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize, - unsigned HOST_WIDE_INT bitnum, enum machine_mode fieldmode, + unsigned HOST_WIDE_INT bitnum, + unsigned HOST_WIDE_INT maxbits, + enum machine_mode fieldmode, rtx value, bool fallback_p) { unsigned int unit @@ -594,7 +600,9 @@ store_bit_field_1 (rtx str_rtx, unsigned if (!store_bit_field_1 (op0, MIN (BITS_PER_WORD, bitsize - i * BITS_PER_WORD), - bitnum + bit_offset, word_mode, + bitnum + bit_offset, + maxbits, + word_mode, value_word, fallback_p)) { delete_insns_since (last); @@ -773,9 +781,10 @@ store_bit_field_1 (rtx str_rtx, unsigned mode. Otherwise, use the smallest mode containing the field. */ if (GET_MODE (op0) == BLKmode + || (maxbits && GET_MODE_BITSIZE (GET_MODE (op0)) > maxbits) || (op_mode != MAX_MACHINE_MODE && GET_MODE_SIZE (GET_MODE (op0)) > GET_MODE_SIZE (op_mode))) - bestmode = get_best_mode (bitsize, bitnum, MEM_ALIGN (op0), + bestmode = get_best_mode (bitsize, bitnum, maxbits, MEM_ALIGN (op0), (op_mode == MAX_MACHINE_MODE ? VOIDmode : op_mode), MEM_VOLATILE_P (op0)); @@ -803,7 +812,7 @@ store_bit_field_1 (rtx str_rtx, unsigned /* Fetch that unit, store the bitfield in it, then store the unit. */ tempreg = copy_to_reg (xop0); - if (store_bit_field_1 (tempreg, bitsize, xbitpos, + if (store_bit_field_1 (tempreg, bitsize, xbitpos, maxbits, fieldmode, orig_value, false)) { emit_move_insn (xop0, tempreg); @@ -816,21 +825,28 @@ store_bit_field_1 (rtx str_rtx, unsigned if (!fallback_p) return false; - store_fixed_bit_field (op0, offset, bitsize, bitpos, value); + store_fixed_bit_field (op0, offset, bitsize, bitpos, maxbits, value); return true; } /* Generate code to store value from rtx VALUE into a bit-field within structure STR_RTX containing BITSIZE bits starting at bit BITNUM. + + MAXBITS is the maximum number of bits we are allowed to store into, + 0 if no limit. + FIELDMODE is the machine-mode of the FIELD_DECL node for this field. */ void store_bit_field (rtx str_rtx, unsigned HOST_WIDE_INT bitsize, - unsigned HOST_WIDE_INT bitnum, enum machine_mode fieldmode, + unsigned HOST_WIDE_INT bitnum, + unsigned HOST_WIDE_INT maxbits, + enum machine_mode fieldmode, rtx value) { - if (!store_bit_field_1 (str_rtx, bitsize, bitnum, fieldmode, value, true)) + if (!store_bit_field_1 (str_rtx, bitsize, bitnum, maxbits, + fieldmode, value, true)) gcc_unreachable (); } @@ -846,7 +862,9 @@ store_bit_field (rtx str_rtx, unsigned H static void store_fixed_bit_field (rtx op0, unsigned HOST_WIDE_INT offset, unsigned HOST_WIDE_INT bitsize, - unsigned HOST_WIDE_INT bitpos, rtx value) + unsigned HOST_WIDE_INT bitpos, + unsigned HOST_WIDE_INT maxbits, + rtx value) { enum machine_mode mode; unsigned int total_bits = BITS_PER_WORD; @@ -867,7 +885,7 @@ store_fixed_bit_field (rtx op0, unsigned /* Special treatment for a bit field split across two registers. */ if (bitsize + bitpos > BITS_PER_WORD) { - store_split_bit_field (op0, bitsize, bitpos, value); + store_split_bit_field (op0, bitsize, bitpos, maxbits, value); return; } } @@ -885,10 +903,12 @@ store_fixed_bit_field (rtx op0, unsigned if (MEM_VOLATILE_P (op0) && GET_MODE_BITSIZE (GET_MODE (op0)) > 0 + && GET_MODE_BITSIZE (GET_MODE (op0)) <= maxbits && flag_strict_volatile_bitfields > 0) mode = GET_MODE (op0); else mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT, + maxbits, MEM_ALIGN (op0), mode, MEM_VOLATILE_P (op0)); if (mode == VOIDmode) @@ -896,7 +916,7 @@ store_fixed_bit_field (rtx op0, unsigned /* The only way this should occur is if the field spans word boundaries. */ store_split_bit_field (op0, bitsize, bitpos + offset * BITS_PER_UNIT, - value); + maxbits, value); return; } @@ -1016,7 +1036,9 @@ store_fixed_bit_field (rtx op0, unsigned static void store_split_bit_field (rtx op0, unsigned HOST_WIDE_INT bitsize, - unsigned HOST_WIDE_INT bitpos, rtx value) + unsigned HOST_WIDE_INT bitpos, + unsigned HOST_WIDE_INT maxbits, + rtx value) { unsigned int unit; unsigned int bitsdone = 0; @@ -1121,7 +1143,7 @@ store_split_bit_field (rtx op0, unsigned /* OFFSET is in UNITs, and UNIT is in bits. store_fixed_bit_field wants offset in bytes. */ store_fixed_bit_field (word, offset * unit / BITS_PER_UNIT, thissize, - thispos, part); + thispos, maxbits, part); bitsdone += thissize; } } @@ -1608,7 +1630,7 @@ extract_bit_field_1 (rtx str_rtx, unsign if (GET_MODE (op0) == BLKmode || (ext_mode != MAX_MACHINE_MODE && GET_MODE_SIZE (GET_MODE (op0)) > GET_MODE_SIZE (ext_mode))) - bestmode = get_best_mode (bitsize, bitnum, MEM_ALIGN (op0), + bestmode = get_best_mode (bitsize, bitnum, 0, MEM_ALIGN (op0), (ext_mode == MAX_MACHINE_MODE ? VOIDmode : ext_mode), MEM_VOLATILE_P (op0)); @@ -1734,7 +1756,7 @@ extract_fixed_bit_field (enum machine_mo mode = tmode; } else - mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT, + mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT, 0, MEM_ALIGN (op0), word_mode, MEM_VOLATILE_P (op0)); if (mode == VOIDmode) Index: Makefile.in =================================================================== --- Makefile.in (revision 170745) +++ Makefile.in (working copy) @@ -2890,7 +2890,7 @@ expr.o : expr.c $(CONFIG_H) $(SYSTEM_H) typeclass.h hard-reg-set.h toplev.h $(DIAGNOSTIC_CORE_H) hard-reg-set.h $(EXCEPT_H) \ reload.h langhooks.h intl.h $(TM_P_H) $(TARGET_H) \ tree-iterator.h gt-expr.h $(MACHMODE_H) $(TIMEVAR_H) $(TREE_FLOW_H) \ - $(TREE_PASS_H) $(DF_H) $(DIAGNOSTIC_H) vecprim.h $(SSAEXPAND_H) + $(TREE_PASS_H) $(DF_H) $(DIAGNOSTIC_H) vecprim.h $(SSAEXPAND_H) $(PARAMS_H) dojump.o : dojump.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(TREE_H) \ $(FLAGS_H) $(FUNCTION_H) $(EXPR_H) $(OPTABS_H) $(INSN_ATTR_H) insn-config.h \ langhooks.h $(GGC_H) gt-dojump.h vecprim.h $(BASIC_BLOCK_H) output.h Index: stmt.c =================================================================== --- stmt.c (revision 170745) +++ stmt.c (working copy) @@ -1758,7 +1758,7 @@ expand_return (tree retval) /* Use bitpos for the source extraction (left justified) and xbitpos for the destination store (right justified). */ - store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode, + store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, 0, word_mode, extract_bit_field (src, bitsize, bitpos % BITS_PER_WORD, 1, false, NULL_RTX, word_mode, word_mode));