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re PR middle-end/50708 (Infinite loop between rshift_double and lshift_double if count is LONG_MIN) 

2012-03-29  Richard Guenther  <rguenther@suse.de>

	PR middle-end/50708
	* double-int.h (rshift_double): Remove.
	* double-int.c (lshift_double): Use absu_hwi to make count
	positive.
	(rshift_double): Make static, take unsigned count argument,
	remove handling of negative count argument.
	(double_int_rshift): Dispatch to lshift_double.

From-SVN: r185951
This commit is contained in:
Richard Guenther 2012-03-29 08:27:04 +00:00 committed by Richard Biener
parent 0b28472897
commit 477fcae3e8
3 changed files with 78 additions and 77 deletions
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10
gcc/ChangeLog
View File

@ -1,3 +1,13 @@
2012-03-29 Richard Guenther <rguenther@suse.de>
PR middle-end/50708
* double-int.h (rshift_double): Remove.
* double-int.c (lshift_double): Use absu_hwi to make count
positive.
(rshift_double): Make static, take unsigned count argument,
remove handling of negative count argument.
(double_int_rshift): Dispatch to lshift_double.
2012-03-28 H.J. Lu <hongjiu.lu@intel.com>
* config/i386/biarch64.h (TARGET_64BIT_DEFAULT): Add

142
gcc/double-int.c
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@ -186,88 +186,19 @@ mul_double_with_sign (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1,
return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
}
/* Shift the doubleword integer in L1, H1 left by COUNT places
keeping only PREC bits of result.
Shift right if COUNT is negative.
ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
void
lshift_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1,
HOST_WIDE_INT count, unsigned int prec,
unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv, bool arith)
{
unsigned HOST_WIDE_INT signmask;
if (count < 0)
{
rshift_double (l1, h1, -count, prec, lv, hv, arith);
return;
}
if (SHIFT_COUNT_TRUNCATED)
count %= prec;
if (count >= 2 * HOST_BITS_PER_WIDE_INT)
{
/* Shifting by the host word size is undefined according to the
ANSI standard, so we must handle this as a special case. */
*hv = 0;
*lv = 0;
}
else if (count >= HOST_BITS_PER_WIDE_INT)
{
*hv = l1 << (count - HOST_BITS_PER_WIDE_INT);
*lv = 0;
}
else
{
*hv = (((unsigned HOST_WIDE_INT) h1 << count)
| (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
? ((unsigned HOST_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
keeping only PREC bits of result. Shift left if COUNT is negative.
ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
keeping only PREC bits of result. ARITH nonzero specifies
arithmetic shifting; otherwise use logical shift.
Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
void
static void
rshift_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1,
HOST_WIDE_INT count, unsigned int prec,
unsigned HOST_WIDE_INT count, unsigned int prec,
unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv,
bool arith)
{
unsigned HOST_WIDE_INT signmask;
if (count < 0)
{
lshift_double (l1, h1, -count, prec, lv, hv, arith);
return;
}
signmask = (arith
? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
: 0);
@ -317,6 +248,69 @@ rshift_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1,
}
}
/* Shift the doubleword integer in L1, H1 left by COUNT places
keeping only PREC bits of result.
Shift right if COUNT is negative.
ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
void
lshift_double (unsigned HOST_WIDE_INT l1, HOST_WIDE_INT h1,
HOST_WIDE_INT count, unsigned int prec,
unsigned HOST_WIDE_INT *lv, HOST_WIDE_INT *hv, bool arith)
{
unsigned HOST_WIDE_INT signmask;
if (count < 0)
{
rshift_double (l1, h1, absu_hwi (count), prec, lv, hv, arith);
return;
}
if (SHIFT_COUNT_TRUNCATED)
count %= prec;
if (count >= 2 * HOST_BITS_PER_WIDE_INT)
{
/* Shifting by the host word size is undefined according to the
ANSI standard, so we must handle this as a special case. */
*hv = 0;
*lv = 0;
}
else if (count >= HOST_BITS_PER_WIDE_INT)
{
*hv = l1 << (count - HOST_BITS_PER_WIDE_INT);
*lv = 0;
}
else
{
*hv = (((unsigned HOST_WIDE_INT) h1 << count)
| (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
? ((unsigned HOST_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;
}
}
/* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
CODE is a tree code for a kind of division, one of
@ -895,7 +889,7 @@ double_int
double_int_rshift (double_int a, HOST_WIDE_INT count, unsigned int prec, bool arith)
{
double_int ret;
rshift_double (a.low, a.high, count, prec, &ret.low, &ret.high, arith);
lshift_double (a.low, a.high, -count, prec, &ret.low, &ret.high, arith);
return ret;
}

3
gcc/double-int.h
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@ -300,9 +300,6 @@ extern int mul_double_with_sign (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
extern void lshift_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
HOST_WIDE_INT, unsigned int,
unsigned HOST_WIDE_INT *, HOST_WIDE_INT *, bool);
extern void rshift_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
HOST_WIDE_INT, unsigned int,
unsigned HOST_WIDE_INT *, HOST_WIDE_INT *, bool);
extern int div_and_round_double (unsigned, int, unsigned HOST_WIDE_INT,
HOST_WIDE_INT, unsigned HOST_WIDE_INT,
HOST_WIDE_INT, unsigned HOST_WIDE_INT *,