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| author | Richard Sandiford <rdsandiford@googlemail.com> | 2012-11-28 20:13:22 +0000 |
|---|---|---|
| committer | Richard Sandiford <rsandifo@gcc.gnu.org> | 2012-11-28 20:13:22 +0000 |
| commit | 00efe3ea3c907b4d7b090da19add210432b3de2c (patch) | |
| tree | aaafc068a028daa1ab2ecddaa3afa63e83019d13 /gcc/stor-layout.c | |
| parent | 1099bb0a712134f8a43e06407292aa95f27c0e54 (diff) | |
| download | gcc-00efe3ea3c907b4d7b090da19add210432b3de2c.zip gcc-00efe3ea3c907b4d7b090da19add210432b3de2c.tar.gz gcc-00efe3ea3c907b4d7b090da19add210432b3de2c.tar.bz2 | |
re PR middle-end/55438 (tmpdir-gcc.dg-struct-layout-1/t001 - t028, gcc.c-torture/execute/991118-1.c, gcc.c-torture/execute/bf64-1.c, ICE)
gcc/
PR middle-end/55438
* expmed.c (simple_mem_bitfield_p): New function, extracted from
store_bit_field_1 and extract_bit_field_1. Use GET_MODE_ALIGNMENT
rather than bitsize when checking the alignment.
(store_bit_field_1, extract_bit_field_1): Call it.
* stor-layout.c (bit_field_mode_iterator::bit_field_mode_iterator):
Don't limit ALIGN_. Assume that memory is mapped in chunks of at
least word size, regardless of BIGGEST_ALIGNMENT.
(bit_field_mode_iterator::get_mode): Use GET_MODE_ALIGNMENT rather
than unit when checking the alignment.
(get_best_mode): Use GET_MODE_ALIGNMENT.
From-SVN: r193905
Diffstat (limited to 'gcc/stor-layout.c')
| -rw-r--r-- | gcc/stor-layout.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c index d0c093f..3d97796 100644 --- a/gcc/stor-layout.c +++ b/gcc/stor-layout.c @@ -2643,15 +2643,17 @@ bit_field_mode_iterator unsigned int align, bool volatilep) : mode_ (GET_CLASS_NARROWEST_MODE (MODE_INT)), bitsize_ (bitsize), bitpos_ (bitpos), bitregion_start_ (bitregion_start), - bitregion_end_ (bitregion_end), align_ (MIN (align, BIGGEST_ALIGNMENT)), + bitregion_end_ (bitregion_end), align_ (align), volatilep_ (volatilep), count_ (0) { if (!bitregion_end_) { - /* We can assume that any aligned chunk of ALIGN_ bits that overlaps + /* We can assume that any aligned chunk of UNITS bits that overlaps the bitfield is mapped and won't trap. */ - bitregion_end_ = bitpos + bitsize + align_ - 1; - bitregion_end_ -= bitregion_end_ % align_ + 1; + unsigned HOST_WIDE_INT units = MIN (align, MAX (BIGGEST_ALIGNMENT, + BITS_PER_WORD)); + bitregion_end_ = bitpos + bitsize + units - 1; + bitregion_end_ -= bitregion_end_ % units + 1; } } @@ -2694,7 +2696,8 @@ bit_field_mode_iterator::next_mode (enum machine_mode *out_mode) break; /* Stop if the mode requires too much alignment. */ - if (unit > align_ && SLOW_UNALIGNED_ACCESS (mode_, align_)) + if (GET_MODE_ALIGNMENT (mode_) > align_ + && SLOW_UNALIGNED_ACCESS (mode_, align_)) break; *out_mode = mode_; @@ -2753,8 +2756,9 @@ get_best_mode (int bitsize, int bitpos, enum machine_mode widest_mode = VOIDmode; enum machine_mode mode; while (iter.next_mode (&mode) - /* ??? For historical reasons, reject modes that are wider than - the alignment. This has both advantages and disadvantages. + /* ??? For historical reasons, reject modes that would normally + receive greater alignment, even if unaligned accesses are + acceptable. This has both advantages and disadvantages. Removing this check means that something like: struct s { unsigned int x; unsigned int y; }; @@ -2808,7 +2812,7 @@ get_best_mode (int bitsize, int bitpos, causes store_bit_field to keep a 128-bit memory reference, so that the final bitfield reference still has a MEM_EXPR and MEM_OFFSET. */ - && GET_MODE_BITSIZE (mode) <= align + && GET_MODE_ALIGNMENT (mode) <= align && (largest_mode == VOIDmode || GET_MODE_SIZE (mode) <= GET_MODE_SIZE (largest_mode))) { |