re: port-macppc/54827: alloca() is broken in gcc 8 on powerpc

[matthew green <mrg%eterna.com.au@localhost>]

a quick look at what -maltivec does that our STACK_BOUNDARY
does, and it seems that maybe there are some hard coded 16
vs 8 cases.. eg, rs6000.c:25131 in -current:

  save_align = (TARGET_ALTIVEC_ABI || DEFAULT_ABI == ABI_DARWIN) ? 16 : 8;

looks like the the one that matters.  there are a few of
these type of conditionals in the code, though the others
seem to all generate warnings, and this one is in the
rs6000_stack_info() function.

as a hack test, can you see if making that always 16 fixes
the problem?  if so, i can figure out a less stupid way.
if not, i'll configure my own test setup for it and see
what else i can figure out.


i remember why we do this.  the idea is that any code that
is built with this compiler will work with altivec code
intermingled with non altivec option code.

thanks.


.mrg.