> Hmm, the function is called at transform time so this shouldn't help
> avoiding the ICE. I expected we refuse to vectorize _any_ reduction
> when sign dependent rounding is in effect? OTOH maybe sign-dependent
> rounding is OK but only when we use a unconditional fold-left
> (so a loop mask from fully masking is OK but not an original COND_ADD?).
So we currently only disable the use of partial vectors
else if (reduction_type == FOLD_LEFT_REDUCTION
&& reduc_fn == IFN_LAST
&& FLOAT_TYPE_P (vectype_in)
&& HONOR_SIGNED_ZEROS (vectype_in)
&& HONOR_SIGN_DEPENDENT_ROUNDING (vectype_in))
{
if (dump_enabled_p ())
dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
"can't operate on partial vectors because"
" signed zeros cannot be preserved.\n");
LOOP_VINFO_CAN_USE_PARTIAL_VECTORS_P (loop_vinfo) = false;
which is inside a LOOP_VINFO_CAN_USE_PARTIAL_VECTORS_P block.
For the fully masked case we continue (and then fail the assertion
on aarch64 at transform time).
I didn't get why that case is ok, though? We still merge the initial
definition with the identity/neutral op (i.e. possibly -0.0) based on
the loop mask. Is that different to partial masking?
Regards
Robin
