🚀 go-pugleaf

Dear support,

When porting gcc for an architecture which has only three hard
registers, I noticed that gcc would ignore some optimizations if 
there are not enough registers.  According to this observation,
I am thinking about providing some virtual registers.  Since these
are actually memory cells,  I definately don't want gcc to use them
for general allocation,  but only for optimizations.

Here is an example:
if a program has 3 dummy variables,  gcc will put them into 3 registers
in order to save a lot of loads/stores.  But if there are only 2 registers
available for this purpose,  gcc will not do such optimization at all.
It would be better if we provide a virtual register, so that gcc can
still do the optimization,  but only 2 of them are actually optimized.

Can this scheme provide better output ?
If so,  how can I tell gcc to use these virtual registers only during
optimizations ?

I think it would be better, for the above example,  if gcc can optimize
the first 2 variables into registers and do load/store for the last one.


Thanks


Dong Lin