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(make_extraction): In BITS_BIG_ENDIAN correction of POS, need to treat

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MEM and REG differently.

From-SVN: r11603
This commit is contained in:
Doug Evans 1996-03-23 22:07:00 +00:00
parent 57b7e1bf86
commit cf54c2cdf2
1 changed files with 15 additions and 6 deletions
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21
gcc/combine.c
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@ -5272,16 +5272,25 @@ make_extraction (mode, inner, pos, pos_rtx, len,
if (BITS_BIG_ENDIAN)
{
/* If position is constant, compute new position. Otherwise,
build subtraction. */
/* POS is passed as if BITS_BIG_ENDIAN == 0, so we need to convert it to
BITS_BIG_ENDIAN style. If position is constant, compute new
position. Otherwise, build subtraction.
Note that POS is relative to the mode of the original argument.
If it's a MEM we need to recompute POS relative to that.
However, if we're extracting from (or inserting into) a register,
we want to recompute POS relative to wanted_inner_mode. */
int width = (GET_CODE (inner) == MEM
? GET_MODE_BITSIZE (is_mode)
: GET_MODE_BITSIZE (wanted_inner_mode));
if (pos_rtx == 0)
pos = GET_MODE_BITSIZE (wanted_inner_mode) - len - pos;
pos = width - len - pos;
else
pos_rtx
= gen_rtx_combine (MINUS, GET_MODE (pos_rtx),
GEN_INT (GET_MODE_BITSIZE (wanted_inner_mode)
- len),
pos_rtx);
GEN_INT (width - len), pos_rtx);
/* POS may be less than 0 now, but we check for that below.
Note that it can only be less than 0 if GET_CODE (inner) != MEM. */
}
/* If INNER has a wider mode, make it smaller. If this is a constant