https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109907
--- Comment #27 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I should note the middle-end could also improve here:
/* If we are comparing a double-word integer with zero or -1, we can
convert the comparison into one involving a single word. */
if (is_int_mode (mode, &int_mode)
&& GET_MODE_BITSIZE (int_mode) == BITS_PER_WORD * 2
&& (!MEM_P (op0) || ! MEM_VOLATILE_P (op0)))
In the case of SImode, GET_MODE_BITSIZE is 32 while BITS_PER_WORD is just 8. We
could use a loop (to generate the and/ior) if GET_MODE_BITSIZE (int_mode) is a
(non-1) multiple of BITS_PER_WORD instead of the 1 expand_binop.
But that is left for another person to do. That would also improve the comment
#20 case too.
Avr might be the only target which supports a mode size that is *4 of the
BIT_PER_WORD fully.
