pa reload problem
John David Anglin
Fri Dec 8 17:07:00 GMT 2000
> On Fri, Dec 08, 2000 at 05:05:21PM -0500, John David Anglin wrote:
> > I am wondering if side_effects_p should return 1 if it encounters
> > an UNSPEC.
> No, because an UNSPEC has no side effects.
> As I said before, the simplest thing is to check for general_operand
> before creating the REG_EQUAL note. Any other solution requires reload
> to Do Things to the INSN_CODE during rematerialization.
It is my impression that the MEM would pass as a general_operand unless
the volatile flag is set. It will pass GO_IF_LEGITIMATE_ADDRESS. Thus,
the general_operand test doesn't look like it will work.
Currently, the unchanging bit is set for the MEM. The comments in
rtl.h say that the bit in a SYMBOL_REF is used for machine specific
purposes. Could it be used to add machine dependent side effects to
a SYMBOL_REF (or possibly an UNSPEC)?
I think Doing Things to the INSN_CODE during rematerialization is too
late unless there is an initial check to determine whether this is possible.
J. David Anglin firstname.lastname@example.org
National Research Council of Canada (613) 990-0752 (FAX: 952-6605)
More information about the Gcc-bugs