> Yeah, I don't think constants are any different here. One fix might be > to use simplify_expand_binop instead of extract_bit_field, as per the > patch below. The patch also restricts the shifting to forward walks, > as discussed in the PR trail.
This looks fine to me, please apply (with a few words added to the comment, e.g. "...doesn't have full wordsize and we transfer in memory order..."). > The point of r8007 seems to be that WORDS_BIG_ENDIAN doesn't apply to > BLKmode fieldmodes, but there must surely be some endianness involved > somewhere, given that we're extracting words from a multiword value? I think that BLKmode objects are treated as left-justified in memory order, i.e. left-justified on big-endian and right-justified on little-endian. > So if possible, I'd prefer to revert the original patch for this PR > and instead adjust the "backwards" test. I'm just not sure whether > it should be "WORDS_BIG_ENDIAN" (reverting r8007, which was obviously > applied for a reason) or something like: > > (fieldmode == BLKmode ? BYTES_BIG_ENDIAN : WORDS_BIG_ENDIAN) This seems to be a little risky for stage 3 though. -- Eric Botcazou
