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Use with_flags for 128-bith arith in aarch64

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Also move the `with_flags` bits and pieces to `prelude.isle` so it can
be shared between backends if necessary.
This commit is contained in:
Alex Crichton
2021-11-19 07:08:08 -08:00
parent 98ce029bbd
commit cbf539abb8
8 changed files with 437 additions and 212 deletions
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44
cranelift/codegen/src/prelude.isle
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@@ -222,3 +222,47 @@
;; Match the instruction that defines the given value, if any.
(decl def_inst (Inst) Value)
(extern extractor def_inst def_inst)
;;;; Helpers for Working with Flags ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Newtype wrapper around `MInst` for instructions that are used for their
;; effect on flags.
(type ProducesFlags (enum (ProducesFlags (inst MInst) (result Reg))))
;; Newtype wrapper around `MInst` for instructions that consume flags.
(type ConsumesFlags (enum (ConsumesFlags (inst MInst) (result Reg))))
;; Combine flags-producing and -consuming instructions together, ensuring that
;; they are emitted back-to-back and no other instructions can be emitted
;; between them and potentially clobber the flags.
;;
;; Returns a `ValueRegs` where the first register is the result of the
;; `ProducesFlags` instruction and the second is the result of the
;; `ConsumesFlags` instruction.
(decl with_flags (ProducesFlags ConsumesFlags) ValueRegs)
(rule (with_flags (ProducesFlags.ProducesFlags producer_inst producer_result)
(ConsumesFlags.ConsumesFlags consumer_inst consumer_result))
(let ((_x Unit (emit producer_inst))
(_y Unit (emit consumer_inst)))
(value_regs producer_result consumer_result)))
;; Like `with_flags` but returns only the result of the consumer operation.
(decl with_flags_1 (ProducesFlags ConsumesFlags) Reg)
(rule (with_flags_1 (ProducesFlags.ProducesFlags producer_inst _producer_result)
(ConsumesFlags.ConsumesFlags consumer_inst consumer_result))
(let ((_x Unit (emit producer_inst))
(_y Unit (emit consumer_inst)))
consumer_result))
;; Like `with_flags` but allows two consumers of the same flags. The result is a
;; `ValueRegs` containing the first consumer's result and then the second
;; consumer's result.
(decl with_flags_2 (ProducesFlags ConsumesFlags ConsumesFlags) ValueRegs)
(rule (with_flags_2 (ProducesFlags.ProducesFlags producer_inst producer_result)
(ConsumesFlags.ConsumesFlags consumer_inst_1 consumer_result_1)
(ConsumesFlags.ConsumesFlags consumer_inst_2 consumer_result_2))
(let ((_x Unit (emit producer_inst))
(_y Unit (emit consumer_inst_1))
(_z Unit (emit consumer_inst_2)))
(value_regs consumer_result_1 consumer_result_2)))