https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63489
Bug ID: 63489
Summary: stack allocated array pointer corrupted
Product: gcc
Version: 4.8.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jonathan.hogg at stfc dot ac.uk
Created attachment 33667
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33667&action=edit
test case
The attached code, when compiled as
g++ -g -O2 testcase.cxx -o testcase && ./testcase
and run, produces:
Try 0x7fff1cbe0a00 0x7fff1cbe0a00
Perm exit: 0 1 2 3 4 5 6 7
GO 0x7fff1cbe0a00
Try2 0x100000000 0x100000000
Segmentation fault
g++ --version:
g++ (Ubuntu 4.8.2-19ubuntu1) 4.8.2
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
The lines "Try" and "Try2" should be identical, as they refer to the same
stack-allocated array perm[]. Running under valgrind is clean until the last
line of ldlt_test() is encountered (which is clearly a segfault as perm is a
bad pointer).
Compiling without -O2 changes something, and the code crashes differently. I
can supply a larger test case (from which this was created) that shuold produce
meaningful answers if the code works correctly, but it will need to be provided
privately for IP reasons.
