https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27214
Richard Biener changed:
What|Removed |Added
Resolution|--- |FIXED
Status|ASSIGNED
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27214
--- Comment #14 from amker at gcc dot gnu.org ---
(In reply to Richard Biener from comment #13)
> The desired cleanup is to make POINTER_PLUS_EXPR take a signed offset
> argument,
> aka ssizetype instead of sizetype.
>
> Bin was working on this a
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27214
Richard Biener changed:
What|Removed |Added
CC||amker at gcc dot gnu.org
--- Comment #1
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27214
Richard Guenther changed:
What|Removed |Added
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed|
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27214
Rich Felker changed:
What|Removed |Added
CC||bugdal at aerifal dot cx
--- Comment #11 fr
--- Comment #10 from rguenth at gcc dot gnu dot org 2008-01-03 15:54
---
"Fixed" only in the sense that we now create
unit size
align 8 symtab 0 alias set -1 canonical type 0x2b6e7ed8c300
precision 8 min max
pointer_to_this >
unsigned DI
--- Comment #9 from pinskia at gcc dot gnu dot org 2007-12-11 00:45 ---
I think this has been fixed by the pointer plus branch merge for 4.3.0.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27214
--- Comment #8 from pinskia at gcc dot gnu dot org 2006-05-05 09:22 ---
Maybe it is time to add POINTER_PLUS_EXPR which should solve the problem (well
95% of the way as what is the type of the 2nd operand, a signed or unsigned
type).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27
--- Comment #7 from joseph at codesourcery dot com 2006-04-19 17:15 ---
Subject: Re: The C frontend introduces undefined pointer overflow
On Wed, 19 Apr 2006, rakdver at gcc dot gnu dot org wrote:
> Andrew, please do not mark PRs as invalid until the people involved in the
> discussio
--- Comment #6 from rakdver at gcc dot gnu dot org 2006-04-19 16:32 ---
I do not think this PR is invalid:
int a[100];
int *p = &a[50];
p - 1 is well defined, and points to 50 - 1 th element of a, as standard
specifies
p + (-1) is also well defined, and points to 50 + (-1) th element,
--- Comment #5 from pinskia at gcc dot gnu dot org 2006-04-19 15:34 ---
Then p + -4 is overflowed already -4 is no different than the unsigned version.
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pinskia at gcc dot gnu dot org changed:
What|Removed |Added
-
--- Comment #4 from rguenth at gcc dot gnu dot org 2006-04-19 15:31 ---
How's that "the same"? Either you say that pointers follow unsigned integer
types in overflow behavior (quote me the standard for that) or explain why
p + -4 is treated as p + (char *)-4
but p - 4 is tre
--- Comment #3 from pinskia at gcc dot gnu dot org 2006-04-19 15:22 ---
Both are those are the same. Maybe we should just get a POINTER_PLUS_EXPR but
that is really not an issue here.
--
pinskia at gcc dot gnu dot org changed:
What|Removed |Added
--- Comment #2 from rguenth at gcc dot gnu dot org 2006-04-19 15:13 ---
"-CST" in this case is unsigned 4294967292, it just happens to be printed as
-4B.
So the addition wraps, as it is done using unsigned arithmetic. Writing
char *foo(char *p)
{
return p + 4294967292;
}
results in
--- Comment #1 from pinskia at gcc dot gnu dot org 2006-04-19 15:06 ---
There is no wrapping here or undefinedness here as far as I can see
You just have to learn that a + "-CST" is the same as a - CST.
--
pinskia at gcc dot gnu dot org changed:
What|Removed
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