On Jan 21, 2009, at 8:40 PM, Uros Bizjak wrote:
Sure, in i386/darwin.h we have:
/* Since we'll never want a stack boundary less aligned than 128 bits
we need the extra work here otherwise bits of gcc get very grumpy
when we ask for lower alignment. We could just reject values less
than 128 bits for Darwin, but it's easier to up the alignment if
it's below the minimum. */
#undef PREFERRED_STACK_BOUNDARY
#define PREFERRED_STACK_BOUNDARY \
MAX (STACK_BOUNDARY, ix86_preferred_stack_boundary)
This selects the maximal alignment to be 128 (16-bytes), the
testcase works for all alignments of 16-bytes or less. For more
aligning, I think that MAX, should be just a MIN:
Er, no.
Er, [ feeling stupid ] shucks. :-( I was thinking the problem was
the instructions to do on demand alignment, fails to be generated in
darwin, because darwin goes out of it's way to say, you don't need to
do that (since we already have 128 aligned stacks), but that code
fails to consider alignments greater than 128, thus causing the failure.
