Question about constraints and reload

[Ulrich Weigand]

Steven Bosscher wrote:

>What is this necessary for, is there any reason to rely on reload to
>turn a constant into a MEM?

Certainly!  Reload will, as one of its options, force a constant to
the literal pool, thereby turning the operand into a MEM.  The s390
port relies extensively on that feature, because we can only use a
limited set of immediate operands, and these differ widely between
different instructions.  Thus the best way to handle constants is
to allow them more or less freely before reload, and have reload
choose to use either an actual immediate operand where available,
reload the constant into a register, or else push it into the
literal pool.

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  weigand@informatik.uni-erlangen.de