[Bug tree-optimization/62173] [5/6 Regression] 64bit Arch can't ivopt while 32bit Arch can

[amker at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62173

--- Comment #40 from amker at gcc dot gnu.org ---
The issue array reference not recognized as IV is resolved now.  From gimple
optimizer's view, there is still another issue in which loop header is bloated
because of lose of signness information.  The root cause is we use sizetype for
addresses, and unsigned type (unsigned int in this case) for loop niter.
We need to prove (sizetype)(unsigned int)(i - 1) equals to (sizetype)(i-1) in
this case by using VRP/loop initial conditions.

I am fixing this now.