* [Bug c++/61872] Assigning to "long double" causes memset to be improperly elided
[not found] <bug-61872-4@http.gcc.gnu.org/bugzilla/>
@ 2014-07-23 12:23 ` rguenth at gcc dot gnu.org
2014-07-23 12:38 ` [Bug target/61872] " rguenth at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-07-23 12:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61872
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |wrong-code
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2014-07-23
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed, mine.
int main()
{
long double a;
__builtin_memset(&a, '\0', sizeof(long double));
a = 1.0;
long double b;
__builtin_memset(&b, '\0', sizeof(long double));
b = 1.0;
if (__builtin_memcmp(&a, &b, sizeof(long double)))
__builtin_abort ();
return 0;
}
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug target/61872] Assigning to "long double" causes memset to be improperly elided
[not found] <bug-61872-4@http.gcc.gnu.org/bugzilla/>
2014-07-23 12:23 ` [Bug c++/61872] Assigning to "long double" causes memset to be improperly elided rguenth at gcc dot gnu.org
@ 2014-07-23 12:38 ` rguenth at gcc dot gnu.org
2020-03-15 22:03 ` ch3root at openwall dot com
2020-03-20 14:25 ` rguenth at gcc dot gnu.org
3 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2014-07-23 12:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61872
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Old value = 12 '\f'
New value = 16 '\020'
init_adjust_machine_modes () at insn-modes.c:1069
1066 /* config/i386/i386-modes.def:34 */
1067 s = TARGET_128BIT_LONG_DOUBLE ? 16 : 12;
1068 mode_size[XFmode] = s;
1069 mode_base_align[XFmode] = s & (~s + 1);
/* In ILP32 mode, XFmode has size 12 and alignment 4.
In LP64 mode, XFmode has size and alignment 16. */
ADJUST_FLOAT_FORMAT (XF, (TARGET_128BIT_LONG_DOUBLE
? &ieee_extended_intel_128_format
: TARGET_96_ROUND_53_LONG_DOUBLE
? &ieee_extended_intel_96_round_53_format
: &ieee_extended_intel_96_format));
ok, but with that you need to adjust the insns to actually store 16bits.
Target bug.
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug target/61872] Assigning to "long double" causes memset to be improperly elided
[not found] <bug-61872-4@http.gcc.gnu.org/bugzilla/>
2014-07-23 12:23 ` [Bug c++/61872] Assigning to "long double" causes memset to be improperly elided rguenth at gcc dot gnu.org
2014-07-23 12:38 ` [Bug target/61872] " rguenth at gcc dot gnu.org
@ 2020-03-15 22:03 ` ch3root at openwall dot com
2020-03-20 14:25 ` rguenth at gcc dot gnu.org
3 siblings, 0 replies; 4+ messages in thread
From: ch3root at openwall dot com @ 2020-03-15 22:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61872
Alexander Cherepanov <ch3root at openwall dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ch3root at openwall dot com
--- Comment #4 from Alexander Cherepanov <ch3root at openwall dot com> ---
This looks like a dup of pr93270, so:
- this is invalid because assignments can change padding;
- this is probably fixed together with pr94103.
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug target/61872] Assigning to "long double" causes memset to be improperly elided
[not found] <bug-61872-4@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2020-03-15 22:03 ` ch3root at openwall dot com
@ 2020-03-20 14:25 ` rguenth at gcc dot gnu.org
3 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2020-03-20 14:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61872
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |DUPLICATE
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
Indeed this one is invalid, the padding becomes undefined after the
long double store.
*** This bug has been marked as a duplicate of bug 93270 ***
^ permalink raw reply [flat|nested] 4+ messages in thread