On Fri, Jan 13, 2012 at 16:07, Tobias Burnus <bur...@net-b.de> wrote: > Dear all, > > the front end uses for array indices (gfc_index_integer_kind / > gfc_array_index_type) which is a signed integer of size POINTER_SIZE. > > The libgfortran library used to use > typedef ssize_t index_type; > which fails if sizeof(void*) is not sizeof(ssize_t); the latter is the case > on LP64 systems (see PR).
As a minor nitpick, not necessarily: E.g. x86_64-linux-gnu and most 64-bit Unix targets are also LP64 (as in, long and pointer are 64 bits), but older releases work there as ssize_t is also 64 bits. The target in the PR is (was?) thus a bit "special", in that while it's LP64, ssize_t is smaller than 64 bits. > For 4.7 this was changed (in April 2011) to: > typedef ptrdiff_t index_type; > which makes more sense - and should be sufficient for LP64 systems. > > However, mixing an POINTER_SIZE type with ptrdiff_t only works if > sizeof(ptrdiff_t) == POINTER_SIZE; in principle, the maximally allowed size > of a variable can be smaller (e.g. page size) than the maximally allowed > pointer size. (sizeof() returns a result of type size_t). I do not know > whether such systems exist in practice and whether such a system is > supported by GCC. > > The attached patch makes let's the FE emit code of the same data type as > used in libgfortran - ptrdiff_t for the array indices. > > Build and regtested on x86-64-linux. > OK for the trunk? Ok, thanks. -- Janne Blomqvist
