When offsetted addresses of global non-static data are computed
multiple times in the same statement the x86_64 backend uses
gen_gotpcrel with offset, which implements an add insn on the
register given. load() uses the R member of the to-be-loaded
value, which doesn't yet have a reg assigned in all cases.
So use the register we're supposed to load the value into as
that register.
The first loop setting up struct arguments must not remove
elements from the vstack (via vtop--), as gen_reg needs them to
potentially evict some argument still held in registers to stack.
Swapping the arg in question to top (and back to its place) also
simplifies the vstore call itself, as not funny save/restore
or some "non-existing" stack elements need to be done.
Generally for a stack a vop-- operation conceptually clobbers
that element, so further references to it aren't allowed anymore.
Removes a premature optimization of char/short loads
rewriting the source type. It did so also for bitfield
loads, thereby removing all the shifts/maskings.
(cond ? 0 : ptr)->member wasn't handled correctly. If one arm
is a null pointer constant (which also can be a pointer) the result
type is that of the other arm.
Michael Matz