For several months, I have been keeping abreast of recent gcc-SVN builds on
several platforms for automatically building and testing a certain free
software project. The build for PowerPC has intermittently given internal
compiler errors. It has been difficult to nail down because the internal error
might go away depending on the state of the project source tree being compiled.
I usually rebuild the gcc-SVN copies once every 1-3 weeks. The gcc build
process follows this pattern:
'svn update' in my local copy of the gcc tree
'mkdir build-gcc' in an unrelated directory
'/path/to/gcc-svn/configure --enable-languages=c
--prefix=/usr/local/gcc-138544-20080801' -- this reflects the last build I
made: SVN revision 138544, built on 2008-08-01
So I build and install the C compiler. When I compile the program in question
(ffmpeg) and the build fails, it happens on one of a few files. With the build
mentioned above, this command fails:
/usr/local/gcc-138544-20080801/bin/gcc -DHAVE_AV_CONFIG_H
-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_ISOC9X_SOURCE -I.
-I"/home/melanson/ffmpeg/ffmpeg-main" -fomit-frame-pointer -maltivec
-mabi=altivec -Wdeclaration-after-statement -Wall -Wno-switch
-Wdisabled-optimization -Wpointer-arith -Wredundant-decls -Wno-pointer-sign
-Wcast-qual -Wwrite-strings -Wtype-limits -O3 -fno-math-errno -fno-signed-zeros
-fPIC -DPIC -c -o libavcodec/dca.o
/home/melanson/ffmpeg/ffmpeg-main/libavcodec/dca.c
This is the error:
/home/melanson/ffmpeg/ffmpeg-main/libavcodec/dca.c: In function
'dca_subsubframe':
/home/melanson/ffmpeg/ffmpeg-main/libavcodec/dca.c:941: warning: array
subscript is above array bounds
/home/melanson/ffmpeg/ffmpeg-main/libavcodec/dca.c:941: warning: array
subscript is above array bounds
/home/melanson/ffmpeg/ffmpeg-main/libavcodec/dca.c:941: warning: array
subscript is above array bounds
/home/melanson/ffmpeg/ffmpeg-main/libavcodec/dca.c: In function
'dca_decode_frame':
/home/melanson/ffmpeg/ffmpeg-main/libavcodec/dca.c:1200: internal compiler
error: in tree_node_structure, at tree.c:2412
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
Now here's the Heisenbug unpredictability: I added -save-temps as requested on
the bug page. The compiler does not crash.
I'm working on a new PPC compiler build right now. I just wanted to finally
enter this bug as a placeholder. I hope to have more data soon.
--
Summary: Heisenbug: SVN of gcc throws internal compiler error on
PPC
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: contact at multimedia dot cx
GCC build triplet: powerpc-unknown-linux-gnu
GCC host triplet: powerpc-unknown-linux-gnu
GCC target triplet: powerpc-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37044
