http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55359
--- Comment #2 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> 2012-11-19 19:00:01 UTC --- Sorry for the breakage. (In reply to comment #1) > Caused by http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=192741 > lowpart_bit_field_p looks weird, I don't see how BITS_PER_WORD is relevant > there, what IMHO matters is whether the subreg is valid or not. While the > first hunk that uses this function uses validate_subreg, the second one > doesn't > and > attempts to create an invalid subreg (subreg:V2DF (reg:OI) 8), where the byte > offset is not a multiple of V2DFmode size. I suppose we're going to have to decide whether simplify_subreg should do the validation itself, or whether it's up to the caller. simplify_subreg asserts things that validate_subreg checks, which implies the latter, but simplify_gen_subreg explicitly calls validate_subreg. Personally I'd prefer it if simplify_subreg and simplify_gen_subreg checked for invalid subregs and return null. Does that sound OK?
