public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug tree-optimization/102706] New: [12 regression] -O2 vectorization causes regression in Warray-bounds-48.c on many targets
@ 2021-10-12 14:29 law at gcc dot gnu.org
  2021-10-12 16:35 ` [Bug tree-optimization/102706] " msebor at gcc dot gnu.org
                   ` (7 more replies)
  0 siblings, 8 replies; 9+ messages in thread
From: law at gcc dot gnu.org @ 2021-10-12 14:29 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102706

            Bug ID: 102706
           Summary: [12 regression] -O2 vectorization causes regression in
                    Warray-bounds-48.c on many targets
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: law at gcc dot gnu.org
  Target Milestone: ---

More fallout from enabling auto-vectorization at -O2.

gcc.dg/Warray-bonds-48.c is regressing on most (but not all) of the embedded
targets.

Just picking one semi-randomly, iq2000-elf:



Running target iq2000-sim
Using /usr/share/dejagnu/baseboards/iq2000-sim.exp as board description file
for target.
Using /usr/share/dejagnu/config/sim.exp as generic interface file for target.
Using /usr/share/dejagnu/baseboards/basic-sim.exp as board description file for
target.
Using
/home/jlaw/jenkins/workspace/iq2000-elf/gcc/gcc/testsuite/config/default.exp as
tool-and-target-specific interface file.
Running /home/jlaw/jenkins/workspace/iq2000-elf/gcc/gcc/testsuite/gcc.dg/dg.exp
...
FAIL: gcc.dg/Warray-bounds-48.c (test for excess errors)

                === gcc Summary ===

# of expected passes            38
# of unexpected failures        1
/home/jlaw/jenkins/workspace/iq2000-elf/iq2000-elf-obj/gcc/gcc/xgcc  version
12.0.0 20211008 (experimental) (GCC)

>From the log file we see:

FAIL: gcc.dg/Warray-bounds-48.c (test for excess errors)
Excess errors:
/home/jlaw/jenkins/workspace/iq2000-elf/gcc/gcc/testsuite/gcc.dg/Warray-bounds-48.c:33:12:
warning: writing 4 bytes into a region of size 0 [-Wstringop-overflow=]
/home/jlaw/jenkins/workspace/iq2000-elf/gcc/gcc/testsuite/gcc.dg/Warray-bounds-48.c:133:12:
warning: writing 4 bytes into a region of size 0 [-Wstringop-overflow=]


My very cursory examination of the test tells me this is a bogus warning.  In
both cases we have allocated enough space to reference array index 0 and 1.


You should be able to reproduce this with a cross compiler without needing a
cross assembler, library, etc.

^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2022-12-08 10:58 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-10-12 14:29 [Bug tree-optimization/102706] New: [12 regression] -O2 vectorization causes regression in Warray-bounds-48.c on many targets law at gcc dot gnu.org
2021-10-12 16:35 ` [Bug tree-optimization/102706] " msebor at gcc dot gnu.org
2021-10-12 19:12 ` pinskia at gcc dot gnu.org
2021-10-13  2:19 ` crazylht at gmail dot com
2021-10-13  2:26 ` crazylht at gmail dot com
2021-10-20  2:13 ` cvs-commit at gcc dot gnu.org
2022-01-19  8:52 ` rguenth at gcc dot gnu.org
2022-01-19  8:55 ` rguenth at gcc dot gnu.org
2022-12-08 10:58 ` cvs-commit at gcc dot gnu.org

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).