Fix PR69752, insn with REG_INC being removed as equiv_init insn

[Bernd Schmidt]

On 02/12/2016 02:18 PM, Jiong Wang wrote:
>>>
>>>     PR rtl-optimization/69752
>>>     * ira.c (update_equiv_regs): When looking for more than a single
>>> SET,
>>>     also take other side effects into account.
>
> Will it be better that we don't remove the insn if it has side-effect
> instead of don't record the equiv?
>
> This can offer more equiv for later rtl optimization?

It's an option I considered, but for stage4 this seems like the safest 
fix. It's not like this is a very common problem, the effect should be 
negligible.


Bernd