[Bug c/26968] New: HDF5 1.7.52 test segfaults with 4.1.0, fine with 4.0.2 (regression)

["orion at cora dot nwra dot com" <gcc-bugzilla at gcc dot gnu dot org>]

Still trying to get more info, but here is what I have.

Trying to build HDF5 1.7.52 on Fedora Core 5 i386 with gcc-4.1.0-3 (also seem
to see it with gcc-4.1.0-4 from rawhide).

The Dataspaces (h5s) test segfaults.

I've tracked it down to the following code in H5Dio.c:2263-2270 (in
H5D_create_chunk_map) apparently not actually setting fm->chunk_dim:

    /* Decide the number of chunks in each dimension*/
    for(u=0; u<f_ndims; u++) {
        /* Keep the size of the chunk dimensions as hsize_t for various
routines */
        fm->chunk_dim[u]=fm->layout->u.chunk.dim[u];

        /* Round up to the next integer # of chunks, to accomodate partial
chunks */
        fm->chunks[u] =
((fm->f_dims[u]+dataset->shared->layout.u.chunk.dim[u])-1) /
dataset->shared->layout.u.chunk.dim[u];
    } /* end for */

Probably is getting optimized away for some reason.  fm->chunk_dim is not
reference again in H5D_create_chunk_map, but it is later on 

I have not been able to distill to a simple test case.

Flags used to compile are the standard RPM_OPT_FLAGS for FC5:

-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector
--param=ssp-buffer-size=4 -m32 -march=i386 -mtune=generic
-fasynchronous-unwind-tables

Flags used with 4.0.2 were:

-O2 -g -pipe -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -m32 -march=i386 -mtune=penti
um4 -fasynchronous-unwind-tables

So there might be something there too....


-- 
           Summary: HDF5 1.7.52 test segfaults with 4.1.0, fine with 4.0.2
                    (regression)
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: orion at cora dot nwra dot com
  GCC host triplet: i386-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26968