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Re: Patch for better support of LEA in HI/QI mode arithmetic.
> On Wed, Apr 14, 1999 at 06:51:22PM +0200, Jan Hubicka wrote:
> > + ;; Combiner is trying to be clever and convert plus operation to ior in
> > some cases.
> > + ;; They are quire common, so we handle them by separate pattern.
> > + (define_insn ""
> > + [(set (match_operand:HI 0 "register_operand" "=r")
> > + (ior:HI (ashift:HI (match_operand:HI 1 "register_operand" "r")
> > + (match_operand:HI 2 "small_shift_operand" "I"))
> > + (match_operand:HI 3 "immediate_operand" "i")))]
>
> Despite the fact that combine is trying to be clever, this is incorrect.
> You are lying to the compiler and it's a fact as sure as tomorrow that
> this will at some point do the wrong thing.
What wrong think?
>
> All this auto widening should certainly be done via post-reload splitters.
> Otherwise sched2 will not know how to allow for AGI stall time.
Well, I am not sure if I understand what do you wnat to say. Why this is
so incorrect?