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ISLE: split algebraic.isle into several files (#6140)

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* ISLE: split algebraic.isle into several files

* delete `algebraic.clif`

* Add `README.md`

* Remove old `algebraic.clif` tests

---------

Co-authored-by: Jamey Sharp <jsharp@fastly.com>
This commit is contained in:
Karl Meakin
2023-04-11 22:39:18 +01:00
committed by GitHub
parent 569089e473
commit b9a58148cf
14 changed files with 919 additions and 910 deletions
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59
cranelift/codegen/src/opts/selects.isle Normal file
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;; `select`/`bitselect`-related rewrites
;; Transform select-of-icmp into {u,s}{min,max} instructions where possible.
(rule (simplify (select ty (sgt _ x y) x y)) (smax ty x y))
(rule (simplify (select ty (sge _ x y) x y)) (smax ty x y))
(rule (simplify (select ty (ugt _ x y) x y)) (umax ty x y))
(rule (simplify (select ty (uge _ x y) x y)) (umax ty x y))
(rule (simplify (select ty (slt _ x y) x y)) (smin ty x y))
(rule (simplify (select ty (sle _ x y) x y)) (smin ty x y))
(rule (simplify (select ty (ult _ x y) x y)) (umin ty x y))
(rule (simplify (select ty (ule _ x y) x y)) (umin ty x y))
;; These are the same rules as above, but when the operands for select are swapped
(rule (simplify (select ty (slt _ x y) y x)) (smax ty x y))
(rule (simplify (select ty (sle _ x y) y x)) (smax ty x y))
(rule (simplify (select ty (ult _ x y) y x)) (umax ty x y))
(rule (simplify (select ty (ule _ x y) y x)) (umax ty x y))
(rule (simplify (select ty (sgt _ x y) y x)) (smin ty x y))
(rule (simplify (select ty (sge _ x y) y x)) (smin ty x y))
(rule (simplify (select ty (ugt _ x y) y x)) (umin ty x y))
(rule (simplify (select ty (uge _ x y) y x)) (umin ty x y))
;; Transform bitselect-of-icmp into {u,s}{min,max} instructions where possible.
(rule (simplify (bitselect ty (sgt _ x y) x y)) (smax ty x y))
(rule (simplify (bitselect ty (sge _ x y) x y)) (smax ty x y))
(rule (simplify (bitselect ty (ugt _ x y) x y)) (umax ty x y))
(rule (simplify (bitselect ty (uge _ x y) x y)) (umax ty x y))
(rule (simplify (bitselect ty (slt _ x y) x y)) (smin ty x y))
(rule (simplify (bitselect ty (sle _ x y) x y)) (smin ty x y))
(rule (simplify (bitselect ty (ult _ x y) x y)) (umin ty x y))
(rule (simplify (bitselect ty (ule _ x y) x y)) (umin ty x y))
;; These are the same rules as above, but when the operands for select are swapped
(rule (simplify (bitselect ty (slt _ x y) y x)) (smax ty x y))
(rule (simplify (bitselect ty (sle _ x y) y x)) (smax ty x y))
(rule (simplify (bitselect ty (ult _ x y) y x)) (umax ty x y))
(rule (simplify (bitselect ty (ule _ x y) y x)) (umax ty x y))
(rule (simplify (bitselect ty (sgt _ x y) y x)) (smin ty x y))
(rule (simplify (bitselect ty (sge _ x y) y x)) (smin ty x y))
(rule (simplify (bitselect ty (ugt _ x y) y x)) (umin ty x y))
(rule (simplify (bitselect ty (uge _ x y) y x)) (umin ty x y))
;; For floats convert fcmp lt into pseudo_min and gt into pseudo_max
;;
;; fmax_pseudo docs state:
;; The behaviour for this operations is defined as fmax_pseudo(a, b) = (a < b) ? b : a, and the behaviour for zero
;; or NaN inputs follows from the behaviour of < with such inputs.
;;
;; That is exactly the operation that we match here!
(rule (simplify
(select ty (fcmp _ (FloatCC.LessThan) x y) x y))
(fmin_pseudo ty x y))
(rule (simplify
(select ty (fcmp _ (FloatCC.GreaterThan) x y) x y))
(fmax_pseudo ty x y))
;; TODO: perform this same optimization to `f{min,max}_pseudo` for vectors
;; with the `bitselect` instruction, but the pattern is a bit more complicated
;; due to most bitselects-over-floats having bitcasts.