http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49479
--- Comment #4 from Tobias Burnus <burnus at gcc dot gnu.org> 2011-06-21 08:58:31 UTC --- (In reply to comment #3) > I think gfortran's convention is - and also TR 29113 requires - that the > addr_expr is not NULL if the variable is allocated - even if it is zero sized. The TR 29113 draft (Interop ML version) has (5.2.3 CFI_cdesc_t) ftp://ftp.nag.co.uk/sc22wg5/N1851-N1900/N1854.pdf "void * base addr; If the object is an unallocated allocatable or a pointer that is disassociated, the value is NULL. If the object has zero size, the value is not NULL but is otherwise processor-dependent. Otherwise [...]" And trans.c has for gfc_call_malloc: /* Call malloc to allocate size bytes of memory, with special conditions: + if size == 0, return a malloced area of size 1, If one looks at RESHAPE in the library: http://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libgfortran/intrinsics/reshape_generic.c;hb=HEAD one sees: 86 if (ret->data == NULL) 87 { 88 rs = 1; 89 for (n = 0; n < rdim; n++) 90 { 91 rex = shape_data[n]; 93 GFC_DIMENSION_SET(ret->dim[n],0,rex - 1,rs); 95 rs *= rex; 96 } 98 ret->data = internal_malloc_size ( rs * size ); Thus, if shape_data[n] == 0 -- which is here the case --, "rs" == 0 and thus one calls malloc with zero size. POSIX states: "If size is 0, either a null pointer or a unique pointer that can be successfully passed to free() shall be returned." Hence, the "rs*size" should be replaced by "MAX(1, rs*size)". I think other intrinsics will have the same problem.
