On Tue, Apr 10, 2012 at 4:56 PM, Richard Guenther <rguent...@suse.de> wrote:
> I'm sure more RTL optimiziation fallout will pop up - and I wonder
> if we should simply avoid modifying the CFG all over the place and
> instead do that in cleanup_cfg. Thus, in the if-conversion case,
> simply do the speculation and leave the empty forwarder blocks
> to be cleaned up by cleanup_cfg (or for CSE to leave unconditional
> jumps conditional, as if (0/1), for example).
The problem with that could be that if(0|1) is not a valid instruction
for every machine. You may need to set a register (pseudo, or hard
reg) that may not be available (e.g. if it is live).