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| author | Ben Gamari <ben@smart-cactus.org> | 2019-09-25 17:26:56 -0400 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2019-11-01 15:48:37 -0400 |
| commit | dab12c8780fe1e6e3c2adb1c9565e2a43aa207db (patch) | |
| tree | 4bdae9fbd47df81e03fbbd54c67d3bcf8880f278 | |
| parent | c751082ca0946f8686453fa2a775809fd027c9c7 (diff) | |
| download | haskell-dab12c8780fe1e6e3c2adb1c9565e2a43aa207db.tar.gz | |
Describe optimisation of demand analysis of noinline
As described in #16588.
| -rw-r--r-- | compiler/basicTypes/MkId.hs | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/compiler/basicTypes/MkId.hs b/compiler/basicTypes/MkId.hs index bc7d0f57c9..d9d23b1235 100644 --- a/compiler/basicTypes/MkId.hs +++ b/compiler/basicTypes/MkId.hs @@ -1595,6 +1595,14 @@ running the simplifier. when we serialize an expression to the interface format. See Note [Inlining and hs-boot files] in ToIface +Note that noinline as currently implemented can hide some simplifications since +it hides strictness from the demand analyser. Specifically, the demand analyser +will treat 'noinline f x' as lazy in 'x', even if the demand signature of 'f' +specifies that it is strict in its argument. We considered fixing this this by adding a +special case to the demand analyser to address #16588. However, the special +case seemed like a large and expensive hammer to address a rare case and +consequently we rather opted to use a more minimal solution. + Note [The oneShot function] ~~~~~~~~~~~~~~~~~~~~~~~~~~~ In the context of making left-folds fuse somewhat okish (see ticket #7994 |