local-alloc update_equiv_regs and moving register initialization

[John Wehle]

> consider
> 
>     if (i)
>       c = a + b;
>     a = i * 3;

The optimization in question requires that the register be set and used
exactly once.  I was going with the requirement that the set appear
prior to the use and known to be executed.

Assuming that code (such as that above) is ignored, any other reason
not to move the initialization when both are within the same loop?

-- John
-------------------------------------------------------------------------
|   Feith Systems  |   Voice: 1-215-646-8000  |  Email: john@feith.com  |
|    John Wehle    |     Fax: 1-215-540-5495  |                         |
-------------------------------------------------------------------------