Information about LTO

[Chris Lattner]

On May 1, 2007, at 9:42 AM, Ian Lance Taylor wrote:

> "Sjodin, Jan" <Jan.Sjodin@amd.com> writes:
>
>> Hi I am new to GCC development and I have a few questions about LTO.
>> What has been done since the last status report in January? I would
>> also like to know what is most important to work on right now to make
>> progress on LTO (e.g. type system, intermediate representation,
>> reader/writer). What remaining work needs to be done to make LTO work
>> for C? In the old status report a few things were mentioned: the  
>> front
>> end was not complete, the type system was not being fully encoded and
>> there are still some things that need to be explicitly represented in
>> the IR.
>
> My take on it.  Others may feel differently.
>
> Some langhooks have been removed.  Removing langhooks one way or
> another is an important step in permitting the middle-end to work
> independently of any frontend.

In addition, other flags that affect codegen and can be mixed and  
matched between translation units need to be adjusted eventually.   
For example, semantic options like -fstrict-aliasing, -ffast-math, - 
fforce-mem, -falign-loops, lots of optimization options (e.g. -fgcse,  
etc), and even target options like -malign-double, -march, etc.

-Chris