Should -fcross-jumping be part of -O1?

[Robert Dewar]

Joe Buck wrote:

> The main purpose of -O0 is for debugging. The user of -O0 wants a
> fast compile and wants to be able to effectively debug.  Accordingly,
> it seems to me that intra-statement optimization is fine, as long as,
> at any point where the user could set a breakpoint, the state matches
> the code (generally meaning that in-memory objects have the correct
> state).  However, what the user would not want is for -O0 to get slower.

We certainly do not want any significant slow downs. However, I suspect
that some very mild attempt to remove junk code would cut down the size
noticeably, and that helps speed up things, for example the link step.