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Detect unrollings of functions in the body of other functions.

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This commit is contained in:
Vincent St-Amour 2011-12-06 18:12:12 -05:00
parent 331d47eb09
commit 742fb7844c
1 changed files with 38 additions and 1 deletions
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39
collects/typed-racket/optimizer/tool/mzc.rkt
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@ -158,8 +158,45 @@
(define head (car group))
(match head ; events are grouped, first element is representative
[(log-entry kind msg stx located-stx pos)
(define n-successes (length (filter success? group)))
;; We consider that a function is a loop if it gets inlined in itself
;; at least once.
;; We treat loops specially, mostly to avoid spurious reports.
;; For instance, if `f' is a loop, and gets inlined in `g' multiple
;; times, it's likely to be unrolling. Same for out-of-fuels in `g'.
;; Therefore, we don't want to report these as inlinings (or failed
;; inlinings).
;; However, we care about `f' being unrolled at least once in `g'.
;; If we run out of fuel trying to inline `f' in `g' for the first
;; time, we report. The reason for this is that it's possible to
;; optimize better if `f''s body inside `g' calls `f' than if `g'
;; calls `f' directly. For instance, `f' may be a loop involving
;; floats, in which case having all calls to `f' originate from `f''s
;; body (as opposed to `g') may make unboxing possible.
;; Of course, we lose precision if `g' has multiple call sites to `f'.
(define n-unrollings (length (filter unrolling? group)))
(define is-a-loop? (> n-unrollings 0))
(define inlining-sites
(group-by equal? #:key (lambda (x)
(inlining-event-where-loc
(inliner-log-entry-inlining-event x)))
group))
(define pruned-group
(if (not is-a-loop?)
group
;; `f' is a loop. We ignore anything beyond the first inlining
;; in `g'.
(apply
append
(for/list ([site (in-list inlining-sites)]
#:when
;; If at least one inlining of `f' in `g', prune.
(not (for/or ([evt (in-list site)])
(success? evt))))
site))))
(define n-successes (length (filter success? group)))
(define n-failures (length (filter failure? group)))
(define n-out-of-fuels (length (filter out-of-fuel? group)))