https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89195
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
While I can see how doing - (HOST_WIDE_INT) len instead of - len fixes the ICE,
I wonder if what make_extraction does isn't invalid.
In particular, we have later on:
/* Unless INNER is not MEM, reject this if we would be spanning bytes or
if the position is not a constant and the length is not 1. In all
other cases, we would only be going outside our object in cases when
an original shift would have been undefined. */
if (MEM_P (inner)
&& ((pos_rtx == 0 && maybe_gt (pos + len, GET_MODE_PRECISION (is_mode)))
|| (pos_rtx != 0 && len != 1)))
return 0;
and I think we need this !maybe_gt (pos + len, GET_MODE_PRECISION (is_mode)))
even in the:
|| (MEM_P (inner) && pos_rtx == 0
&& (pos
% (STRICT_ALIGNMENT ? GET_MODE_ALIGNMENT (tmode)
: BITS_PER_UNIT)) == 0
/* We can't do this if we are widening INNER_MODE (it
may not be aligned, for one thing). */
&& !paradoxical_subreg_p (tmode, inner_mode)
&& (inner_mode == tmode
|| (! mode_dependent_address_p (XEXP (inner, 0),
MEM_ADDR_SPACE (inner))
&& ! MEM_VOLATILE_P (inner))))))
conditions, because otherwise we have a MEM and we try to read some other bytes
outside of that MEM, but those might not be accessible at all etc.
So, add && known_le (pos + len, GET_MODE_PRECISION (is_mode)) here?
