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fold-const.c (lshift_double): Honor PREC. 

* fold-const.c (lshift_double): Honor PREC.
	(rshift_double): Likewise.

From-SVN: r46872
This commit is contained in:
John Wehle 2001-11-09 05:27:51 +00:00 committed by John Wehle
parent 702020d658
commit 11b161d069
2 changed files with 54 additions and 8 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
Fri Nov 9 00:25:18 EST 2001 John Wehle (john@feith.com)
* fold-const.c (lshift_double): Honor PREC.
(rshift_double): Likewise.
2001-11-08 Kazu Hirata <kazu@hxi.com>
* config/1750a/1750a.c: Fix comment formatting.

57
gcc/fold-const.c
View File

@ -383,6 +383,8 @@ lshift_double (l1, h1, count, prec, lv, hv, arith)
HOST_WIDE_INT *hv;
int arith;
{
unsigned HOST_WIDE_INT signmask;
if (count < 0)
{
rshift_double (l1, h1, -count, prec, lv, hv, arith);
@ -412,6 +414,26 @@ lshift_double (l1, h1, count, prec, lv, hv, arith)
| (l1 >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1));
*lv = l1 << count;
}
/* Sign extend all bits that are beyond the precision. */
signmask = -((prec > HOST_BITS_PER_WIDE_INT
? (*hv >> (prec - HOST_BITS_PER_WIDE_INT - 1))
: (*lv >> (prec - 1))) & 1);
if (prec >= 2 * HOST_BITS_PER_WIDE_INT)
;
else if (prec >= HOST_BITS_PER_WIDE_INT)
{
*hv &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
*hv |= signmask << (prec - HOST_BITS_PER_WIDE_INT);
}
else
{
*hv = signmask;
*lv &= ~((unsigned HOST_WIDE_INT) (-1) << prec);
*lv |= signmask << prec;
}
}
/* Shift the doubleword integer in L1, H1 right by COUNT places
@ -423,7 +445,7 @@ void
rshift_double (l1, h1, count, prec, lv, hv, arith)
unsigned HOST_WIDE_INT l1;
HOST_WIDE_INT h1, count;
unsigned int prec ATTRIBUTE_UNUSED;
unsigned int prec;
unsigned HOST_WIDE_INT *lv;
HOST_WIDE_INT *hv;
int arith;
@ -443,21 +465,40 @@ rshift_double (l1, h1, count, prec, lv, hv, arith)
{
/* Shifting by the host word size is undefined according to the
ANSI standard, so we must handle this as a special case. */
*hv = signmask;
*lv = signmask;
*hv = 0;
*lv = 0;
}
else if (count >= HOST_BITS_PER_WIDE_INT)
{
*hv = signmask;
*lv = ((signmask << (2 * HOST_BITS_PER_WIDE_INT - count - 1) << 1)
| ((unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT)));
*hv = 0;
*lv = (unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT);
}
else
{
*hv = (unsigned HOST_WIDE_INT) h1 >> count;
*lv = ((l1 >> count)
| ((unsigned HOST_WIDE_INT) h1 << (HOST_BITS_PER_WIDE_INT - count - 1) << 1));
*hv = ((signmask << (HOST_BITS_PER_WIDE_INT - count))
| ((unsigned HOST_WIDE_INT) h1 >> count));
}
/* Zero / sign extend all bits that are beyond the precision. */
if (count >= (HOST_WIDE_INT)prec)
{
*hv = signmask;
*lv = signmask;
}
else if ((prec - count) >= 2 * HOST_BITS_PER_WIDE_INT)
;
else if ((prec - count) >= HOST_BITS_PER_WIDE_INT)
{
*hv &= ~((HOST_WIDE_INT) (-1) << (prec - count - HOST_BITS_PER_WIDE_INT));
*hv |= signmask << (prec - count - HOST_BITS_PER_WIDE_INT);
}
else
{
*hv = signmask;
*lv &= ~((unsigned HOST_WIDE_INT) (-1) << (prec - count));
*lv |= signmask << (prec - count);
}
}