llvm dev - Sep 2010 - [LLVMdev] using GCC LTO files as a frontend to dragonegg?

On Mon, Sep 13, 2010 at 04:27, Duncan Sands <baldrick at free.fr> wrote:
> Hopefully this is feasible, as I said I didn't work on
> it yet.
It sounds doable, but I'm not sure why would you want to convert the
gimple into LLVM bitcode, if you are already saving LLVM bitcode in
the file.  Wouldn't you be just duplicating code?


Diego.

Hi Diego,
>> Hopefully this is feasible, as I said I didn't work on
>> it yet.
>
> It sounds doable, but I'm not sure why would you want to convert the
> gimple into LLVM bitcode, if you are already saving LLVM bitcode in
> the file.  Wouldn't you be just duplicating code?
here I was thinking of the possibility that some files have been compiled with
-flto but without the dragonegg plugin, so contain gimple in the assembler,
while others have been compiled with dragonegg so contain LLVM bitcode in the
assembler.  By converting the gimple into LLVM IR they can all be mutually
optimized together.  This might be important if distributions start shipping
standard libraries compiled with -flto.

Ciao,

Duncan.

By the way, the GIMPLE front end (the GCC branch) would seem to be
appealing for use in conjunction with LLVM.  The idea being to be able to
select what stages of GCC compilation were compiled.   (The front end
appears it is some way off from being usable.)

Marcus

On Mon, Sep 13, 2010 at 03:14:19PM +0200, Duncan Sands
wrote:
> Hi Diego,
> 
> >> Hopefully this is feasible, as I said I didn't work on
> >> it yet.
> >
> > It sounds doable, but I'm not sure why would you want to convert
the
> > gimple into LLVM bitcode, if you are already saving LLVM bitcode in
> > the file.  Wouldn't you be just duplicating code?
> 
> here I was thinking of the possibility that some files have been compiled
with
> -flto but without the dragonegg plugin, so contain gimple in the assembler,
> while others have been compiled with dragonegg so contain LLVM bitcode in
the
> assembler.  By converting the gimple into LLVM IR they can all be mutually
> optimized together.  This might be important if distributions start
shipping
> standard libraries compiled with -flto.
Duncan,
   FYI, all of the dragon-egg targets now fully support lto in current gcc
trunk (since we were able to default lto on for darwin last week).
         Jack
> 
> Ciao,
> 
> Duncan.
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> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

On Mon, Sep 13, 2010 at 09:14, Duncan Sands <baldrick at free.fr> wrote:
> By converting the gimple into LLVM IR they can all be mutually
> optimized together.  This might be important if distributions start
shipping
> standard libraries compiled with -flto.
Ah, I see.  Yes, that's a good idea.


Diego.

On Mon, Sep 13, 2010 at 09:42, Marcus G. Daniels <mdaniels at lanl.gov>
wrote:
> (The front end appears it is some way off from being usable.)
Indeed.  Currently, it's only a part-time effort.  Perhaps we'll be
ready to merge into trunk by next spring (further follow-ups to gcc@,
please).


Diego.