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| author | Ben Gamari <ben@smart-cactus.org> | 2020-03-24 13:13:43 -0400 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2020-12-14 13:37:09 -0500 |
| commit | 7e9debd4ceb068effe8ac81892d2cabcb8f55850 (patch) | |
| tree | f222f3f3e5d662a12ab00fcb1a81d8e8dfb6c0de /testsuite/tests/simplCore/should_compile | |
| parent | c696bb2f4476e0ce4071e0d91687c1fe84405599 (diff) | |
| download | haskell-7e9debd4ceb068effe8ac81892d2cabcb8f55850.tar.gz | |
Optimise nullary type constructor usage
During the compilation of programs GHC very frequently deals with
the `Type` type, which is a synonym of `TYPE 'LiftedRep`. This patch
teaches GHC to avoid expanding the `Type` synonym (and other nullary
type synonyms) during type comparisons, saving a good amount of work.
This optimisation is described in `Note [Comparing nullary type
synonyms]`.
To maximize the impact of this optimisation, we introduce a few
special-cases to reduce `TYPE 'LiftedRep` to `Type`. See
`Note [Prefer Type over TYPE 'LiftedPtrRep]`.
Closes #17958.
Metric Decrease:
T18698b
T1969
T12227
T12545
T12707
T14683
T3064
T5631
T5642
T9020
T9630
T9872a
T13035
haddock.Cabal
haddock.base
Diffstat (limited to 'testsuite/tests/simplCore/should_compile')
| -rw-r--r-- | testsuite/tests/simplCore/should_compile/T13143.stderr | 6 | ||||
| -rw-r--r-- | testsuite/tests/simplCore/should_compile/T18013.stderr | 4 | ||||
| -rw-r--r-- | testsuite/tests/simplCore/should_compile/T7360.stderr | 4 |
3 files changed, 7 insertions, 7 deletions
diff --git a/testsuite/tests/simplCore/should_compile/T13143.stderr b/testsuite/tests/simplCore/should_compile/T13143.stderr index 44ab565425..c2bc42a872 100644 --- a/testsuite/tests/simplCore/should_compile/T13143.stderr +++ b/testsuite/tests/simplCore/should_compile/T13143.stderr @@ -1,17 +1,17 @@ ==================== Tidy Core ==================== Result size of Tidy Core - = {terms: 71, types: 44, coercions: 0, joins: 0/0} + = {terms: 71, types: 40, coercions: 0, joins: 0/0} Rec { --- RHS size: {terms: 4, types: 4, coercions: 0, joins: 0/0} +-- RHS size: {terms: 4, types: 3, coercions: 0, joins: 0/0} T13143.$wf [InlPrag=NOINLINE, Occ=LoopBreaker] :: forall {a}. (# #) -> a [GblId, Arity=1, Str=<B>b, Cpr=b, Unf=OtherCon []] T13143.$wf = \ (@a) _ [Occ=Dead] -> T13143.$wf @a GHC.Prim.(##) end Rec } --- RHS size: {terms: 4, types: 4, coercions: 0, joins: 0/0} +-- RHS size: {terms: 4, types: 3, coercions: 0, joins: 0/0} f [InlPrag=[final]] :: forall a. Int -> a [GblId, Arity=1, diff --git a/testsuite/tests/simplCore/should_compile/T18013.stderr b/testsuite/tests/simplCore/should_compile/T18013.stderr index 51e30a9f75..20cb606cb4 100644 --- a/testsuite/tests/simplCore/should_compile/T18013.stderr +++ b/testsuite/tests/simplCore/should_compile/T18013.stderr @@ -129,9 +129,9 @@ Rule fired: Class op fmap (BUILTIN) ==================== Tidy Core ==================== Result size of Tidy Core - = {terms: 52, types: 106, coercions: 17, joins: 0/1} + = {terms: 52, types: 101, coercions: 17, joins: 0/1} --- RHS size: {terms: 37, types: 87, coercions: 17, joins: 0/1} +-- RHS size: {terms: 37, types: 84, coercions: 17, joins: 0/1} mapMaybeRule :: forall a b. Rule IO a b -> Rule IO (Maybe a) (Maybe b) [GblId, diff --git a/testsuite/tests/simplCore/should_compile/T7360.stderr b/testsuite/tests/simplCore/should_compile/T7360.stderr index 73bafb04f6..21fe15d4f5 100644 --- a/testsuite/tests/simplCore/should_compile/T7360.stderr +++ b/testsuite/tests/simplCore/should_compile/T7360.stderr @@ -1,7 +1,7 @@ ==================== Tidy Core ==================== Result size of Tidy Core - = {terms: 106, types: 47, coercions: 0, joins: 0/0} + = {terms: 106, types: 45, coercions: 0, joins: 0/0} -- RHS size: {terms: 6, types: 3, coercions: 0, joins: 0/0} T7360.$WFoo3 [InlPrag=INLINE[final] CONLIKE] :: Int %1 -> Foo @@ -31,7 +31,7 @@ T7360.fun4 :: () WorkFree=False, Expandable=False, Guidance=IF_ARGS [] 20 0}] T7360.fun4 = fun1 T7360.Foo1 --- RHS size: {terms: 11, types: 8, coercions: 0, joins: 0/0} +-- RHS size: {terms: 11, types: 7, coercions: 0, joins: 0/0} fun2 :: forall {a}. [a] -> ((), Int) [GblId, Arity=1, |