alignment must be is based on elementary datatypes, but does not
take into account the alignment requirements of FP spills. Such
are present in jmp_buf. The memory allocator is used by the JPEG
and PNG libraries as well and the JPEG library has a jmp_buf in
one of its structures.
Another problem case is the "long double" type. This datatype is
not in the list of elementary types on which the minimal alignment
is based and can also be used by imported source code.
The patch forces 16-byte alignment on ia64.
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