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[RFC] cortex-a{53,57}-simd.md missing?


Hi all.

This is a question related with current development of Aarch64 backend.

In latest trunk revision of GCC 5.0, in directory gcc/config/arm there are following files:

cortex-a{8,9,15,17}.md
cortex-a{8,9,15,17}-neon.md

These files contain constructions like

(define_insn_reservation insn-name default_latency condition regexp)

for both scalar and vector (NEON) instructions.

But for AdvSIMD aarch64 instructions in cortex-a53.md only the following lines can be found:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Crude Advanced SIMD approximation.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(define_insn_reservation "cortex_53_advsimd" 4
  (and (eq_attr "tune" "cortexa53")
       (eq_attr:q "is_neon_type" "yes"))
  "cortex_a53_simd0")

Does it mean that all AdvSIMD instructions for cortex-a53 are supposed to be of latency = 4?

In cortex-a57.md the description for "neon" instructions is more full, it contains a lot of statements for different SIMD instructions.
It appeared in trunk just a month ago.

Are there any plans to release detailed pipeline descriptions for SIMD instructions for cortex-a53?
How can it influence the performance of the generated code?

--
Best regards,
Ilya Palachev


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