Re: [PPC] Fix 16796

[Andrew Pinski <pinskia at physics dot uc dot edu>]

On Nov 10, 2004, at 1:00 PM, Nathan Sidwell wrote:

> This is a partial fix for 16796 where we emit a load into rA
> and then copy rA to rB.  It is partial, because this patch fixes
> SF and DF mode regs, but not the integer mode registers.
>
> What is happening is that flow2 replaces conditional branches
> to the exit block with conditional return instructions.  After this,
> the only path to the exit block is merged, and the load and the
> move are now in the same bb.  It is not entirely the fault of the
> register allocator -- we shouldn't really be changing cfg so
> significantly after register allocation.

Really this should be done not by peepholes at all but by some
other thing like maybe a combiner after we duplication the block.
This will help so much other code that we will not have to do
any tricks likes this again.

-- Pinski