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Re: [mips patch RFA] handle trap_if with DI-mode arguments.
cgd@broadcom.com writes:
> At 13 Aug 2003 23:06:49 +0100, Richard Sandiford wrote:
> > > And the nonmemory_operand -> arith_operand change should (possibly
> > > ever so slightly) help the performance of the compiler, one would
> > > hope?
> >
> > Yeah. mips_gen_conditional_trap makes sure that the second operand
> > is within range. But with nonmemory_operand, combine might turn:
> >
> > r1 = 0x12345
> > trap_if r2 = r1
> >
> > into:
> >
> > trap_if r2 = 0x12345
Dumb example, sorry: r1 = 0x12345 isn't valid. Read 0x12340000 instead.
> why would it do that?
>
> i mean, it it just "because it can, and because the predicates don't
> prevent it from doing so?" (the constraints coming into play at a
> different time?)
Right.