compiler: improve register use when compiling calls.

* share/txr/stdlib/compiler.tl (compiler comp-call-impl):
Instead of allocating N temporary registers for N arguments,
some (or even none) of which may actually be used, we
do this one argument at a time: allocate just one register,
compile the argument expression, and then free the register
immediately if that fragment specifies its own output location
instead of the register. Otherwise keep the register and push
it on a stack.  This strategy lowers maximum register use.
Also, since we are pushing the used registers on a stack,
when we call free-tregs, they get liberated in reverse
order of allocation, which keeps things tidy.

0 files changed, 0 insertions, 0 deletions