https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752
--- Comment #31 from Robbert gcc at robbertkrebbers dot nl ---
[oops, that was meant to be private, please remove my last comment]
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752
--- Comment #12 from Robbert gcc at robbertkrebbers dot nl ---
(In reply to Richard Biener from comment #10)
and see how this will make PTA useless (all pointers passed to a function
whose result might be used in a way to take advantage
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752
--- Comment #8 from Robbert gcc at robbertkrebbers dot nl ---
(In reply to Richard Biener from comment #7)
Other testcase:
int main()
{
int *p;
int x = 0;
if (p == x)
*p = 1;
return x;
}
we optimize this to return 0. You
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752
--- Comment #5 from Robbert gcc at robbertkrebbers dot nl ---
(In reply to Richard Biener from comment #4)
as the address is not live after that.
Why doesn't gcc consider casting a pointer to an integer as making it live?
The concrete
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752
--- Comment #9 from Robbert gcc at robbertkrebbers dot nl ---
(In reply to Richard Biener from comment #6)
which fixes the testcase (but is incomplete - equivalences built on
gimple assignment RHS need to be considered as well).
Can you give
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752
--- Comment #3 from Robbert gcc at robbertkrebbers dot nl ---
(In reply to Robbert from comment #2)
* Writing the representation of a chunk of memory containing pointers to
memory.
to memory should be to disk
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752
--- Comment #2 from Robbert gcc at robbertkrebbers dot nl ---
This example may seem academic, but there is a real problem underneath.
Of course, I do agree that optimizations based on pointer origins are useful,
but it is not an all or nothing
Assignee: unassigned at gcc dot gnu.org
Reporter: gcc at robbertkrebbers dot nl
The following program prints 0 instead of the expected 15:
#include stdio.h
#include stdint.h
#include limits.h
int main() {
int x = 0, *p = 0;
for (uintptr_t i = 0; ; i++) {
if (i
: unassigned at gcc dot gnu.org
Reporter: gcc at robbertkrebbers dot nl
Consider the following example:
#includestdio.h
#includestdint.h
int main() {
int x = 1, y = 2, *p = y, *q = x + 1;
if ((intptr_t)p == (intptr_t)q) {
*q = 10;
printf(%d %d %d\n, x, y, p == q
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54945
--- Comment #12 from gcc at robbertkrebbers dot nl 2012-10-18 15:59:00 UTC ---
What do you mean by invalid? It is certainly not undefined behavior. The
pointer x + 1 is allowed by (6.5.6p8 of C11), and the equality operator
should behave
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54945
Bug #: 54945
Summary: Too strong non-aliasing analysis?
Classification: Unclassified
Product: gcc
Version: 4.7.1
Status: UNCONFIRMED
Severity: normal
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