Difference between two optimization settings

[Ian Lance Taylor]

Thomas Heinz <thomasheinz@gmx.net> writes:

> Do you (or someone else) know how to enable only constant propagation + 
> constant folding in an -O0 optimization setting?

gcc does not support that.

> I guess it's necessary to tweak the code, isn't it?
> If so, how much effort would it be?

It would be non-trivial.  The CCP pass in gcc uses SSA form.  With -O0
SSA form is not generated.

Ian