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(expand_call): Correctly handle returning BLKmode structures in registers when...

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(expand_call): Correctly handle returning BLKmode structures in
registers when the size of the structure is not a multiple of
word_size.

From-SVN: r10051
This commit is contained in:
Richard Kenner 1995-06-22 23:01:03 -04:00
parent 8ecb1d9245
commit 1b5c58730b
1 changed files with 41 additions and 28 deletions
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69
gcc/calls.c
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@ -2047,6 +2047,9 @@ expand_call (exp, target, ignore)
int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
int i;
enum machine_mode tmpmode;
rtx src, dst;
int bitsize = MIN (TYPE_ALIGN (TREE_TYPE (exp)), BITS_PER_WORD);
int bitpos, xbitpos, big_endian_correction = 0;
if (target == 0)
{
@ -2055,38 +2058,48 @@ expand_call (exp, target, ignore)
preserve_temp_slots (target);
}
/* We could probably emit more efficient code for machines
/* Structures whose size is not a multiple of a word are aligned
to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
machine, this means we must skip the empty high order bytes when
calculating the bit offset. */
if (BYTES_BIG_ENDIAN && bytes % UNITS_PER_WORD)
big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
* BITS_PER_UNIT));
/* Copy the structure BITSIZE bites at a time.
We could probably emit more efficient code for machines
which do not use strict alignment, but it doesn't seem
worth the effort at the current time. */
for (i = 0; i < n_regs; i++)
for (bitpos = 0, xbitpos = big_endian_correction;
bitpos < bytes * BITS_PER_UNIT;
bitpos += bitsize, xbitpos += bitsize)
{
rtx src = operand_subword_force (valreg, i, BLKmode);
rtx dst = operand_subword (target, i, 1, BLKmode);
int bitsize = MIN (TYPE_ALIGN (TREE_TYPE (exp)), BITS_PER_WORD);
int bitpos, big_endian_correction = 0;
/* Should never happen. */
if (src == NULL || dst == NULL)
abort ();
if (BYTES_BIG_ENDIAN && bytes < UNITS_PER_WORD)
big_endian_correction
= (BITS_PER_WORD - (bytes * BITS_PER_UNIT));
for (bitpos = 0;
bitpos < BITS_PER_WORD && bytes > 0;
bitpos += bitsize, bytes -= bitsize / BITS_PER_UNIT)
{
int xbitpos = bitpos + big_endian_correction;
/* We need a new source operand each time xbitpos is on a
word boundary and when xbitpos == big_endian_correction
(the first time through). */
if (xbitpos % BITS_PER_WORD == 0
|| xbitpos == big_endian_correction)
src = operand_subword_force (valreg,
xbitpos / BITS_PER_WORD,
BLKmode);
/* We need a new destination operand each time bitpos is on
a word boundary. */
if (bitpos % BITS_PER_WORD == 0)
dst = operand_subword (target, bitpos / BITS_PER_WORD, 1, BLKmode);
store_bit_field (dst, bitsize, xbitpos, word_mode,
extract_bit_field (src, bitsize, bitpos, 1,
NULL_RTX, word_mode,
word_mode,
bitsize / BITS_PER_UNIT,
BITS_PER_WORD),
bitsize / BITS_PER_UNIT, BITS_PER_WORD);
}
/* Use xbitpos for the source extraction (right justified) and
xbitpos for the destination store (left justified). */
store_bit_field (dst, bitsize, bitpos % BITS_PER_WORD, word_mode,
extract_bit_field (src, bitsize,
xbitpos % BITS_PER_WORD, 1,
NULL_RTX, word_mode,
word_mode,
bitsize / BITS_PER_UNIT,
BITS_PER_WORD),
bitsize / BITS_PER_UNIT, BITS_PER_WORD);
}
}
else