[Bug rtl-optimization/63156] web can't handle AUTOINC correctly

[carrot at google dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63156

--- Comment #8 from Carrot <carrot at google dot com> ---
(In reply to Steven Bosscher from comment #7)
> (In reply to Carrot from comment #6)
> > Since it is intentionally to remove flag DF_REF_READ_WRITE on use,
> 
> Ah, but I don't think that was the correct fix. The DEF and USE refs should
> both have the flag set.

I agree it's more reasonable to set DF_REF_READ_WRITE flag on both use and def,
it means we need to revert r125736 and reopen bug 32339.