------- Comment #1 from hjl at lucon dot org 2007-10-10 13:52 -------
There are
-- Macro: STACK_BOUNDARY
Define this macro to the minimum alignment enforced by hardware
for the stack pointer on this machine. The definition is a C
expression for the desired alignment (measured in bits). This
value is used as a default if `PREFERRED_STACK_BOUNDARY' is not
defined. On most machines, this should be the same as
`PARM_BOUNDARY'.
-- Macro: PREFERRED_STACK_BOUNDARY
Define this macro if you wish to preserve a certain alignment for
the stack pointer, greater than what the hardware enforces. The
definition is a C expression for the desired alignment (measured
in bits). This macro must evaluate to a value equal to or larger
than `STACK_BOUNDARY'.
For psABI conformance, we need INCOMING_STACK_BOUNDARY, which is specified
by the psABI. For backends with INCOMING_STACK_BOUNDARY support,
PREFERRED_STACK_BOUNDARY is used for outgoing stack alignment only. That
means
STACK_BOUNDARY <= PREFERRED_STACK_BOUNDARY <= INCOMING_STACK_BOUNDARY
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33721
