[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #12 from rguenth at gcc dot gnu dot org 2010-01-02 19:40 --- Looks like invalid code in the first place. -- rguenth at gcc dot gnu dot org changed: What|Removed |Added Status|NEW |RESOLVED Resolution||INVALID http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #11 from l dot jirkovsky at gmail dot com 2009-01-29 11:19 --- First, I'd like to thank you for doing this hard work and for finding out which patch causes this problem. Anyway I've done more investigation to the problematic code. The problem actually begins in CachedFileImageIteratorBase::operator*() In correct build (without optimizations, with debugging enabled or with --param inline-unit-growth=60) the currentRow pointer is pointer to ordinary array, I'm guessing it's array of unsigned shorts. But in segfaulting build my debugger (gdb) shows me, that currentRow is: vigra::TinyVectorBaseunsigned char, 3, unsigned char [3], vigra::TinyVectorunsigned char, 3 which _data structure doesn't exist in memory. Because it deems really weird I'm not sure the debugger was right (it was run with higly optimized code when only some parts of enblend actually had debugging information on). However if I'm wrong in previous statement, the currentRow should still be valid. I'd took if I was trying to access, lets say, currentRow[1000] which could be out of array bounds, but this code segfaults when I'm trying to access currentRow[0]. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #8 from hjl dot tools at gmail dot com 2009-01-11 23:32 --- This patch http://gcc.gnu.org/ml/gcc-patches/2007-02/msg00886.html triggers this crash. It failed at -O1. With gcc 4.4, it failed at -O2. -- hjl dot tools at gmail dot com changed: What|Removed |Added CC||hjl dot tools at gmail dot ||com Last reconfirmed|-00-00 00:00:00 |2009-01-11 23:32:10 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #9 from hjl dot tools at gmail dot com 2009-01-11 23:33 --- There are warnings like ../include/vigra/accessor.hxx: In function âvoid vigra::read_bands(vigra::Decoder*, ImageIterator, Accessor, SrcValueType) [with ImageIterator = vigra::CachedFileImageIteratorvigra::RGBValuedouble, 0u, 1u, 2u , Accessor = vigra::RGBAccessorvigra::RGBValuedouble, 0u, 1u, 2u , SrcValueType = double]â: ../include/vigra/accessor.hxx:813: warning: array subscript is above array bounds In file included from enblend.h:39, from enblend.cc:124: ../include/vigra/diff2d.hxx: In function âvoid enblend::maskBounds(MaskType*, vigra::Rect2D, vigra::Rect2D) [with MaskType = enblend::enblendMain(std::listvigra::ImageImportInfo*, std::allocatorvigra::ImageImportInfo* , vigra::ImageExportInfo, vigra::Rect2D) [with ImagePixelType = vigra::RGBValueunsigned char, 0u, 1u, 2u]::MaskType]â: ../include/vigra/diff2d.hxx:1108: warning: assuming signed overflow does not occur when assuming that (X - c) X is always false -- hjl dot tools at gmail dot com changed: What|Removed |Added Last reconfirmed|2009-01-11 23:32:10 |2009-01-11 23:33:14 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #10 from hjl dot tools at gmail dot com 2009-01-11 23:46 --- Adding --param inline-unit-growth=60 fixed gcc 4.4 revision 143274 at -O2. -- hjl dot tools at gmail dot com changed: What|Removed |Added CC||jh at suse dot cz Status|WAITING |NEW Ever Confirmed|0 |1 Last reconfirmed|2009-01-11 23:33:14 |2009-01-11 23:46:52 date|| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #6 from l dot jirkovsky at gmail dot com 2009-01-10 16:42 --- I've tried it with gcc 4.2.4 and it works perfectly, so it have to be caused by some change between 4.2.4 and 4.3.2. I'll try to use svn to find out which commit causes this. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #7 from l dot jirkovsky at gmail dot com 2009-01-10 16:47 --- I've forgot to post info about gcc 4.2.4: $ gcc -v Using built-in specs. Target: i686-pc-linux-gnu Configured with: ../gcc-4.2.4/configure --prefix=/home/lukas/gcc --enable-shared --enable-languages=c,c++ --enable-threads=posix --enable-__cxa_atexit Thread model: posix gcc version 4.2.4 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #1 from pinskia at gcc dot gnu dot org 2008-12-25 15:36 --- I think it can be somewhat connected to bug #32896. Unlikely. Anyways does it segfault when compiled at -O0. How about -O2 -fno-strict-aliasing ? -- pinskia at gcc dot gnu dot org changed: What|Removed |Added Status|UNCONFIRMED |WAITING http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #2 from l dot jirkovsky at gmail dot com 2008-12-25 17:25 --- I've already tested it with -O2 -fno-strict-aliasing without success. I'll test it with -O0. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #3 from l dot jirkovsky at gmail dot com 2008-12-25 18:07 --- with -O0 no segfault -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #4 from pinskia at gcc dot gnu dot org 2008-12-25 18:09 --- How about -O2 -fno-strict-overflow ? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
[Bug c++/38625] Segmentation fault when dereferencing valid pointer, probably REGRESSION
--- Comment #5 from l dot jirkovsky at gmail dot com 2008-12-25 18:51 --- -O2 -fno-strict-overflow also segfaults -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38625
