--- gcc/stor-layout.c.jj 2011-03-11 12:16:39.000000000 +0100 +++ gcc/stor-layout.c 2011-03-31 15:58:05.000000000 +0200 @@ -2445,7 +2445,8 @@ fixup_unsigned_type (tree type) enum machine_mode get_best_mode (int bitsize, int bitpos, unsigned int align, - enum machine_mode largest_mode, int volatilep) + enum machine_mode largest_mode, int volatilep, + tree type) { enum machine_mode mode; unsigned int unit = 0; @@ -2484,7 +2485,12 @@ get_best_mode (int bitsize, int bitpos, && unit <= BITS_PER_WORD && unit <= MIN (align, BIGGEST_ALIGNMENT) && (largest_mode == VOIDmode - || unit <= GET_MODE_BITSIZE (largest_mode))) + || unit <= GET_MODE_BITSIZE (largest_mode)) + && (type == NULL_TREE + || !host_integerp (TYPE_SIZE (type), 1) + || bitpos + (unsigned HOST_WIDE_INT) GET_MODE_BITSIZE (tmode) + <= (unsigned HOST_WIDE_INT) + tree_low_cst (TYPE_SIZE (type), 1))) wide_mode = tmode; } --- gcc/rtl.h.jj 2011-03-31 08:51:04.000000000 +0200 +++ gcc/rtl.h 2011-03-31 14:07:18.000000000 +0200 @@ -2525,6 +2525,11 @@ extern bool expensive_function_p (int); extern unsigned int variable_tracking_main (void); /* In stor-layout.c. */ + +/* Find the best mode to use to access a bit field. */ +extern enum machine_mode get_best_mode (int, int, unsigned int, + enum machine_mode, int, tree); + extern void get_mode_bounds (enum machine_mode, int, enum machine_mode, rtx *, rtx *); --- gcc/machmode.h.jj 2011-01-06 10:21:52.000000000 +0100 +++ gcc/machmode.h 2011-03-31 14:06:54.000000000 +0200 @@ -246,11 +246,6 @@ extern enum machine_mode int_mode_for_mo extern enum machine_mode mode_for_vector (enum machine_mode, unsigned); -/* Find the best mode to use to access a bit field. */ - -extern enum machine_mode get_best_mode (int, int, unsigned int, - enum machine_mode, int); - /* Determine alignment, 1<=result<=BIGGEST_ALIGNMENT. */ extern CONST_MODE_BASE_ALIGN unsigned char mode_base_align[NUM_MACHINE_MODES]; --- gcc/expmed.c.jj 2011-03-31 08:50:43.000000000 +0200 +++ gcc/expmed.c 2011-03-31 16:21:25.000000000 +0200 @@ -47,9 +47,9 @@ 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, rtx, rtx); static void store_split_bit_field (rtx, unsigned HOST_WIDE_INT, - unsigned HOST_WIDE_INT, rtx); + unsigned HOST_WIDE_INT, rtx, rtx); static rtx extract_fixed_bit_field (enum machine_mode, rtx, unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT, @@ -334,7 +334,7 @@ mode_for_extraction (enum extraction_pat static bool store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize, unsigned HOST_WIDE_INT bitnum, enum machine_mode fieldmode, - rtx value, bool fallback_p) + rtx value, bool fallback_p, rtx orig_mem) { unsigned int unit = (MEM_P (str_rtx)) ? BITS_PER_UNIT : BITS_PER_WORD; @@ -542,7 +542,7 @@ 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, - value_word, fallback_p)) + value_word, fallback_p, orig_mem)) { delete_insns_since (last); return false; @@ -714,10 +714,18 @@ store_bit_field_1 (rtx str_rtx, unsigned if (GET_MODE (op0) == BLKmode || (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 + (orig_mem && MEM_EXPR (orig_mem) + && MEM_OFFSET (orig_mem) + ? INTVAL (MEM_OFFSET (orig_mem)) + : 0), + MEM_ALIGN (op0), (op_mode == MAX_MACHINE_MODE ? VOIDmode : op_mode), - MEM_VOLATILE_P (op0)); + MEM_VOLATILE_P (op0), + orig_mem && MEM_EXPR (orig_mem) + ? TREE_TYPE (MEM_EXPR (orig_mem)) + : NULL_TREE); else bestmode = GET_MODE (op0); @@ -743,7 +751,7 @@ store_bit_field_1 (rtx str_rtx, unsigned the unit. */ tempreg = copy_to_reg (xop0); if (store_bit_field_1 (tempreg, bitsize, xbitpos, - fieldmode, orig_value, false)) + fieldmode, orig_value, false, NULL_RTX)) { emit_move_insn (xop0, tempreg); return true; @@ -755,7 +763,7 @@ 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, value, orig_mem); return true; } @@ -769,7 +777,8 @@ store_bit_field (rtx str_rtx, unsigned H unsigned HOST_WIDE_INT bitnum, 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, fieldmode, value, true, + MEM_P (str_rtx) ? str_rtx : NULL_RTX)) gcc_unreachable (); } @@ -785,7 +794,7 @@ 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, rtx value, rtx orig_mem) { enum machine_mode mode; unsigned int total_bits = BITS_PER_WORD; @@ -806,7 +815,7 @@ 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, value, NULL_RTX); return; } } @@ -827,15 +836,21 @@ store_fixed_bit_field (rtx op0, unsigned && flag_strict_volatile_bitfields > 0) mode = GET_MODE (op0); else - mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT, - MEM_ALIGN (op0), mode, MEM_VOLATILE_P (op0)); + mode = get_best_mode (bitsize, + bitpos + offset * BITS_PER_UNIT + + (orig_mem && MEM_EXPR (orig_mem) + && MEM_OFFSET (orig_mem) + ? INTVAL (MEM_OFFSET (orig_mem)) : 0), + MEM_ALIGN (op0), mode, MEM_VOLATILE_P (op0), + orig_mem && MEM_EXPR (orig_mem) + ? TREE_TYPE (MEM_EXPR (orig_mem)) : NULL_TREE); if (mode == VOIDmode) { /* 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); + value, orig_mem); return; } @@ -955,7 +970,7 @@ 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, rtx value, rtx orig_mem) { unsigned int unit; unsigned int bitsdone = 0; @@ -1060,7 +1075,7 @@ 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, part, orig_mem); bitsdone += thissize; } } @@ -1511,7 +1526,7 @@ extract_bit_field_1 (rtx str_rtx, unsign bestmode = get_best_mode (bitsize, bitnum, MEM_ALIGN (op0), (ext_mode == MAX_MACHINE_MODE ? VOIDmode : ext_mode), - MEM_VOLATILE_P (op0)); + MEM_VOLATILE_P (op0), NULL_TREE); else bestmode = GET_MODE (op0); @@ -1635,7 +1650,8 @@ extract_fixed_bit_field (enum machine_mo } else mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT, - MEM_ALIGN (op0), word_mode, MEM_VOLATILE_P (op0)); + MEM_ALIGN (op0), word_mode, MEM_VOLATILE_P (op0), + NULL_TREE); if (mode == VOIDmode) /* The only way this should occur is if the field spans word --- gcc/expr.c.jj 2011-03-31 08:51:03.000000000 +0200 +++ gcc/expr.c 2011-03-31 16:23:36.000000000 +0200 @@ -3997,8 +3997,13 @@ 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, - MEM_ALIGN (str_rtx), str_mode, 0); + str_mode = get_best_mode (bitsize, + bitpos + (MEM_EXPR (str_rtx) + && MEM_OFFSET (str_rtx) + ? INTVAL (MEM_OFFSET (str_rtx)) : 0), + MEM_ALIGN (str_rtx), str_mode, 0, + MEM_EXPR (str_rtx) + ? TREE_TYPE (MEM_EXPR (str_rtx)) : NULL_TREE); if (str_mode == VOIDmode) return false; str_bitsize = GET_MODE_BITSIZE (str_mode); --- gcc/fold-const.c.jj 2011-03-31 08:51:02.000000000 +0200 +++ gcc/fold-const.c 2011-03-31 15:29:59.000000000 +0200 @@ -3411,7 +3411,7 @@ optimize_bit_field_compare (location_t l const_p ? TYPE_ALIGN (TREE_TYPE (linner)) : MIN (TYPE_ALIGN (TREE_TYPE (linner)), TYPE_ALIGN (TREE_TYPE (rinner))), - word_mode, lvolatilep || rvolatilep); + word_mode, lvolatilep || rvolatilep, NULL_TREE); if (nmode == VOIDmode) return 0; @@ -5237,7 +5237,7 @@ fold_truthop (location_t loc, enum tree_ end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize); lnmode = get_best_mode (end_bit - first_bit, first_bit, TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode, - volatilep); + volatilep, NULL_TREE); if (lnmode == VOIDmode) return 0; @@ -5302,7 +5302,7 @@ fold_truthop (location_t loc, enum tree_ end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize); rnmode = get_best_mode (end_bit - first_bit, first_bit, TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode, - volatilep); + volatilep, NULL_TREE); if (rnmode == VOIDmode) return 0; --- gcc/testsuite/gcc.c-torture/execute/pr48124.c.jj 2011-04-01 10:53:07.000000000 +0200 +++ gcc/testsuite/gcc.c-torture/execute/pr48124.c 2011-04-01 10:53:26.000000000 +0200 @@ -0,0 +1,32 @@ +/* PR middle-end/48124 */ + +extern void abort (void); + +struct S +{ + signed a : 26; + signed b : 16; + signed c : 10; + volatile signed d : 14; +}; + +static struct S e = { 0, 0, 0, 1 }; +static int f = 1; + +void __attribute__((noinline)) +foo (void) +{ + e.d = 0; + f = 2; +} + +int +main () +{ + if (e.a || e.b || e.c || e.d != 1 || f != 1) + abort (); + foo (); + if (e.a || e.b || e.c || e.d || f != 2) + abort (); + return 0; +} --- gcc/testsuite/gcc.dg/pr48124.c.jj 2011-04-01 10:52:55.000000000 +0200 +++ gcc/testsuite/gcc.dg/pr48124.c 2011-04-01 10:53:40.000000000 +0200 @@ -0,0 +1,34 @@ +/* PR middle-end/48124 */ +/* { dg-do run } */ +/* { dg-options "-Os -fno-toplevel-reorder" } */ + +extern void abort (void); + +struct S +{ + signed a : 26; + signed b : 16; + signed c : 10; + volatile signed d : 14; +}; + +static struct S e = { 0, 0, 0, 1 }; +static int f = 1; + +void __attribute__((noinline)) +foo (void) +{ + e.d = 0; + f = 2; +} + +int +main () +{ + if (e.a || e.b || e.c || e.d != 1 || f != 1) + abort (); + foo (); + if (e.a || e.b || e.c || e.d || f != 2) + abort (); + return 0; +}