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Diffstat (limited to 'testsuite/tests/profiling/should_compile/T19894/inline.hs')
| -rw-r--r-- | testsuite/tests/profiling/should_compile/T19894/inline.hs | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/testsuite/tests/profiling/should_compile/T19894/inline.hs b/testsuite/tests/profiling/should_compile/T19894/inline.hs new file mode 100644 index 0000000000..daa7ec659e --- /dev/null +++ b/testsuite/tests/profiling/should_compile/T19894/inline.hs @@ -0,0 +1,27 @@ +-- We use fromStreamK/toStreamK to convert the direct style stream to CPS +-- style. In the first phase we try fusing the fromStreamK/toStreamK using: +-- +-- {-# RULES "fromStreamK/toStreamK fusion" +-- forall s. toStreamK (fromStreamK s) = s #-} +-- +-- If for some reason some of the operations could not be fused then we have +-- fallback rules in the second phase. For example: +-- +-- {-# INLINE_EARLY unfoldr #-} +-- unfoldr :: (Monad m, IsStream t) => (b -> Maybe (a, b)) -> b -> t m a +-- unfoldr step seed = fromStreamS (S.unfoldr step seed) +-- {-# RULES "unfoldr fallback to StreamK" [1] +-- forall a b. S.toStreamK (S.unfoldr a b) = K.unfoldr a b #-}``` +-- +-- Then, fromStreamK/toStreamK are inlined in the last phase: +-- +-- {-# INLINE_LATE toStreamK #-} +-- toStreamK :: Monad m => Stream m a -> K.Stream m a``` +-- +-- The fallback rules make sure that if we could not fuse the direct style +-- operations then better use the CPS style operation, because unfused direct +-- style would have worse performance than the CPS style ops. + +#define INLINE_EARLY INLINE [2] +#define INLINE_NORMAL INLINE [1] +#define INLINE_LATE INLINE [0] |