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Commit 00efe3ea by Richard Sandiford Committed by Richard Sandiford
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re PR middle-end/55438 (tmpdir-gcc.dg-struct-layout-1/t001 - t028, … 

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
parent 1099bb0a
Showing with 43 additions and 20 deletions
gcc/ChangeLog
2012-11-28 Richard Sandiford <rdsandiford@googlemail.com>
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.
2012-11-28 Vladimir Makarov <vmakarov@redhat.com>
PR rtl-optimization/55512
gcc/expmed.c
......@@ -416,6 +416,21 @@ lowpart_bit_field_p (unsigned HOST_WIDE_INT bitnum,
else
return bitnum % BITS_PER_WORD == 0;
}
/* Return true if OP is a memory and if a bitfield of size BITSIZE at
bit number BITNUM can be treated as a simple value of mode MODE. */
static bool
simple_mem_bitfield_p (rtx op0, unsigned HOST_WIDE_INT bitsize,
unsigned HOST_WIDE_INT bitnum, enum machine_mode mode)
{
return (MEM_P (op0)
&& bitnum % BITS_PER_UNIT == 0
&& bitsize == GET_MODE_BITSIZE (mode)
&& (!SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (op0))
|| (bitnum % GET_MODE_ALIGNMENT (mode) == 0
&& MEM_ALIGN (op0) >= GET_MODE_ALIGNMENT (mode))));
}
/* Try to use instruction INSV to store VALUE into a field of OP0.
BITSIZE and BITNUM are as for store_bit_field. */
......@@ -624,12 +639,7 @@ store_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
/* If the target is memory, storing any naturally aligned field can be
done with a simple store. For targets that support fast unaligned
memory, any naturally sized, unit aligned field can be done directly. */
if (MEM_P (op0)
&& bitnum % BITS_PER_UNIT == 0
&& bitsize == GET_MODE_BITSIZE (fieldmode)
&& (!SLOW_UNALIGNED_ACCESS (fieldmode, MEM_ALIGN (op0))
|| (bitnum % bitsize == 0
&& MEM_ALIGN (op0) % bitsize == 0)))
if (simple_mem_bitfield_p (op0, bitsize, bitnum, fieldmode))
{
op0 = adjust_bitfield_address (op0, fieldmode, bitnum / BITS_PER_UNIT);
emit_move_insn (op0, value);
......@@ -1455,12 +1465,7 @@ extract_bit_field_1 (rtx str_rtx, unsigned HOST_WIDE_INT bitsize,
/* Extraction of a full MODE1 value can be done with a load as long as
the field is on a byte boundary and is sufficiently aligned. */
if (MEM_P (op0)
&& bitnum % BITS_PER_UNIT == 0
&& bitsize == GET_MODE_BITSIZE (mode1)
&& (!SLOW_UNALIGNED_ACCESS (mode1, MEM_ALIGN (op0))
|| (bitnum % bitsize == 0
&& MEM_ALIGN (op0) % bitsize == 0)))
if (simple_mem_bitfield_p (op0, bitsize, bitnum, mode1))
{
op0 = adjust_bitfield_address (op0, mode1, bitnum / BITS_PER_UNIT);
return convert_extracted_bit_field (op0, mode, tmode, unsignedp);
......
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)))
{
......
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