[Bug middle-end/63477] [6/7/8 Regression] Bogus warning with -O3 -Warray-bounds: array subscript is above array bounds
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63477 --- Comment #5 from Martin Sebor --- (In reply to Alexandre Ganea from comment #4) The test case has been reduced a little too far -- it reads an uninitialized variable: for (unsigned i;; i++) for (; i;) if (j[i] == j[0]) h.e(); But the false positive can also be reproduced by initializing the variable to zero. Can you please open a new bug with the corrected test case?
[Bug middle-end/63477] [6/7/8 Regression] Bogus warning with -O3 -Warray-bounds: array subscript is above array bounds
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63477
Alexandre Ganea changed:
What|Removed |Added
CC||alexandre.ganea at ubisoft dot
com
--- Comment #4 from Alexandre Ganea ---
Hi,
We get what seems like a spurious warning at the following location in LLVM:
https://github.com/llvm/llvm-project/blob/master/llvm/lib/Target/AMDGPU/R600ISelLowering.cpp#L1718
The warning is:
//warning: array subscript is above array bounds [-Warray-bounds]
//if (NewBldVec[i] == NewBldVec[j]) {
//~~~^
This only occurs when compiling with GCC 7.1+ and 9.1/trunk (not with 8), with
-O3 -Warray-bounds
This has been creduce'd to:
class a {
int b;
unsigned c;
public:
bool operator==(a) { return b && c; }
};
class d {
public:
void e();
};
class f {
a g(d &) const;
};
a f::g(d ) const {
a j[1];
for (unsigned i;; i++)
for (; i;)
if (j[i] == j[0])
h.e();
}
Could you please confirm the issue?
Thank you!
[Bug middle-end/63477] [6/7/8 Regression] Bogus warning with -O3 -Warray-bounds: array subscript is above array bounds
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63477 --- Comment #2 from Martin Sebor --- Author: msebor Date: Thu Nov 16 16:48:36 2017 New Revision: 254833 URL: https://gcc.gnu.org/viewcvs?rev=254833=gcc=rev Log: PR middle-end/63477 - Bogus warning with -O3 -Warray-bounds: array subscript is above array bounds gcc/testsuite/ChangeLog: PR middle-end/63477 * gcc.dg/pr63477.c: New test. Added: trunk/gcc/testsuite/gcc.dg/pr63477.c Modified: trunk/gcc/testsuite/ChangeLog
[Bug middle-end/63477] [6/7/8 Regression] Bogus warning with -O3 -Warray-bounds: array subscript is above array bounds
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63477 Martin Sebor changed: What|Removed |Added Status|NEW |RESOLVED Known to work||8.0 Resolution|--- |FIXED Known to fail|8.0 | --- Comment #3 from Martin Sebor --- Strangely, I cannot reproduce this warning anymore with GCC 8. Bisection points to r220157 (gcc 5.0.0) as the revision that fixed it. I've added the test case to the test suite in r254833 and with that I'm resolving this bug as fixed. Please reopen it if the problem reappears.
[Bug middle-end/63477] [6/7/8 Regression] Bogus warning with -O3 -Warray-bounds: array subscript is above array bounds
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63477 Richard Biener changed: What|Removed |Added Target Milestone|--- |6.5
[Bug middle-end/63477] [6/7/8 Regression] Bogus warning with -O3 -Warray-bounds: array subscript is above array bounds
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63477 Martin Sebor changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2017-10-17 CC||hubicka at gcc dot gnu.org, ||msebor at gcc dot gnu.org Known to work||4.7.4 Summary|Bogus warning with -O3 |[6/7/8 Regression] Bogus |-Warray-bounds: array |warning with -O3 |subscript is above array|-Warray-bounds: array |bounds |subscript is above array ||bounds Ever confirmed|0 |1 Known to fail||4.8.3, 4.9.3, 5.3.0, 6.2.0, ||7.1.0, 8.0 --- Comment #1 from Martin Sebor --- Confirmed. The first revision to trigger the error is r192990 (gcc 4.8.0) so marking this a regression.
