procyberian/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

re PR target/82274 (__builtin_mul_overflow fails to detect overflow for int64_t when compiled with -m32)

Browse source 
PR target/82274
	* internal-fn.c (expand_mul_overflow): If both operands have
	the same highpart of -1 or 0 and the topmost bit of lowpart
	is different, overflow is if res <= 0 rather than res < 0.

	* libgcc2.c (__mulvDI3): If both operands have
	the same highpart of -1 and the topmost bit of lowpart is 0,
	multiplication overflows even if both lowparts are 0.

	* gcc.dg/pr82274-1.c: New test.
	* gcc.dg/pr82274-2.c: New test.

From-SVN: r253734
This commit is contained in:
Jakub Jelinek 2017-10-13 19:19:12 +02:00 • committed by Jakub Jelinek
parent 8de7190350
commit e7176f75d6
7 changed files with 67 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
gcc/ChangeLog
View file

@ -1,3 +1,10 @@
2017-10-13 Jakub Jelinek <jakub@redhat.com>
PR target/82274
* internal-fn.c (expand_mul_overflow): If both operands have
the same highpart of -1 or 0 and the topmost bit of lowpart
is different, overflow is if res <= 0 rather than res < 0.
2017-10-13 Pat Haugen <pthaugen@us.ibm.com>
* config/rs6000/rs6000.c (rs6000_builtin_vectorization_cost): Remove

6
gcc/internal-fn.c
View file

@ -1770,8 +1770,8 @@ expand_mul_overflow (location_t loc, tree lhs, tree arg0, tree arg1,
}
/* At this point hipart{0,1} are both in [-1, 0]. If they are
the same, overflow happened if res is negative, if they are
different, overflow happened if res is positive. */
the same, overflow happened if res is non-positive, if they
are different, overflow happened if res is positive. */
if (op0_sign != 1 && op1_sign != 1 && op0_sign != op1_sign)
emit_jump (hipart_different);
else if (op0_sign == 1 || op1_sign == 1)
@ -1779,7 +1779,7 @@ expand_mul_overflow (location_t loc, tree lhs, tree arg0, tree arg1,
NULL_RTX, NULL, hipart_different,
profile_probability::even ());
do_compare_rtx_and_jump (res, const0_rtx, LT, false, mode,
do_compare_rtx_and_jump (res, const0_rtx, LE, false, mode,
NULL_RTX, NULL, do_error,
profile_probability::very_unlikely ());
emit_jump (done_label);

6
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,9 @@
2017-10-13 Jakub Jelinek <jakub@redhat.com>
PR target/82274
* gcc.dg/pr82274-1.c: New test.
* gcc.dg/pr82274-2.c: New test.
2017-10-13 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/80873

16
gcc/testsuite/gcc.dg/pr82274-1.c Normal file
View file

@ -0,0 +1,16 @@
/* PR target/82274 */
/* { dg-do run } */
/* { dg-shouldfail "trapv" } */
/* { dg-options "-ftrapv" } */
int
main ()
{
#ifdef __SIZEOF_INT128__
volatile __int128 m = -(((__int128) 1) << (__CHAR_BIT__ * __SIZEOF_INT128__ / 2));
#else
volatile long long m = -(1LL << (__CHAR_BIT__ * __SIZEOF_LONG_LONG__ / 2));
#endif
m = m * m;
return 0;
}

26
gcc/testsuite/gcc.dg/pr82274-2.c Normal file
View file

@ -0,0 +1,26 @@
/* PR target/82274 */
/* { dg-do run } */
/* { dg-options "-O2" } */
int
main ()
{
#ifdef __SIZEOF_INT128__
__int128 m = -(((__int128) 1) << (__CHAR_BIT__ * __SIZEOF_INT128__ / 2));
volatile __int128 mv = m;
__int128 r;
#else
long long m = -(1LL << (__CHAR_BIT__ * __SIZEOF_LONG_LONG__ / 2));
volatile long long mv = m;
long long r;
#endif
if (!__builtin_mul_overflow (mv, mv, &r))
__builtin_abort ();
if (!__builtin_mul_overflow_p (mv, mv, r))
__builtin_abort ();
if (!__builtin_mul_overflow (m, m, &r))
__builtin_abort ();
if (!__builtin_mul_overflow_p (m, m, r))
__builtin_abort ();
return 0;
}

7
libgcc/ChangeLog
View file

@ -1,3 +1,10 @@
2017-10-13 Jakub Jelinek <jakub@redhat.com>
PR target/82274
* libgcc2.c (__mulvDI3): If both operands have
the same highpart of -1 and the topmost bit of lowpart is 0,
multiplication overflows even if both lowparts are 0.
2017-09-28 James Bowman <james.bowman@ftdichip.com>
* config/ft32/crti-hw.S: Add watchdog vector, FT930 IRQ support.

3
libgcc/libgcc2.c
View file

@ -375,7 +375,8 @@ __mulvDI3 (DWtype u, DWtype v)
}
else
{
if (uu.s.high == (Wtype) -1 && vv.s.high == (Wtype) - 1)
if ((uu.s.high & vv.s.high) == (Wtype) -1
&& (uu.s.low | vv.s.low) != 0)
{
DWunion ww = {.ll = (UDWtype) (UWtype) uu.s.low
* (UDWtype) (UWtype) vv.s.low};