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Re: Base register restrictions
Thanks. I thought that if I just try to disallow this in the operand
predicates/constraints in my define_insn patterns, I would end up
getting an unrecognizable instruction error. I will try that and see
what happens.
Brice
On Jun 29, 2009, at 5:11 PM, Ian Lance Taylor wrote:
Dobes <bdobry@udel.edu> writes:
I am working on a port to an architecture with some strict rules.
The
restriction that I am unable to figure out how to enforce is a base
register
that is allowed in the destination operand, but not in a source
operand.
For example, this would be allowed "add 4($1), $8, $9", but this
would not
be allowed "add $8, 4($1), $9" because $1 can only be used a base
register
for the destination operand. Is there any way to get that kind of
information in GO_IF_LEGITIMATE_ADDRESS or can you think of some
other way
to handle this? Anyone know of a port with something similar that
I could
look at? Thanks.
This kind of restriction would normally be handled via appropriate use
of register classes in the define_insn patterns. You will also want
to
make sure that BASE_REG_CLASS and REGNO_OK_FOR_BASE_P are definedly
correctly.
Ian