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targed.md: copy_to_mode_reg or force_reg?
- From: Georg-Johann Lay <avr at gjlay dot de>
- To: gcc at gcc dot gnu dot org
- Date: Mon, 16 Feb 2009 16:52:54 +0100
- Subject: targed.md: copy_to_mode_reg or force_reg?
Hi,
in machine description expanders the functions copy_to_mode_reg and and
force_reg from explow.c can be used to ensure that an operand lives in a
register.
But what function should be used?
What are the differences? The only difference I can depict from the
comment is that an operand returned by force_reg must not be altered,
i.e. overwritten afterwards.
Are there any pitfalls using these functions with respect to
reload_completed, reload_in_progress or no_new_pseudos?
As far as I understand, these function can only be used if
no_new_pseudos is false.
Thanks, Georg-Johann