https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63184
--- Comment #11 from Jeffrey A. Law <law at redhat dot com> --- So could we reassociate the address arithmetic in match.pd so that we fold away the pointer computation in favor of index adjustment in the ARRAY_REF? Do we have to worry about overflow in address reassociation? Using the gimple from c#2: i.0_3 = i; _4 = i.0_3 * 4; _5 = (sizetype) _4; _6 = _5 + 4; _7 = &a[1] + _6; _9 = i.0_3 + 2; _10 = &a[_9]; if (_7 != _10) Transform it into: i.0_3 = i; temp = i.0_3 + 1 + 1; /* +1 from pointer arith, +1 from array index ] _4 = i.0_3 * 4; /* DEAD */ _5 = (sizetype) _4; /* DEAD */ _6 = _5 + 4; /* DEAD */ _7 = &a[temp]; _9 = i.0_3 + 2; _10 = &a[_9]; if (_7 != _10) That gives us a fighting chance to see that temp is equivalent to _9 and that the ultimate addresses are equal.
