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| author | Sebastian Graf <sebastian.graf@kit.edu> | 2020-11-03 18:28:49 +0100 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2020-11-20 02:09:51 -0500 |
| commit | 321d1bd8a79ab39c3c9e8697fffb0107c43f83cf (patch) | |
| tree | ee3b1476f7bffafd318607a3963a79ee47f4e9f7 | |
| parent | b57845c3d80f5bed8f498f27fb7a318f2b2f8b2c (diff) | |
| download | haskell-321d1bd8a79ab39c3c9e8697fffb0107c43f83cf.tar.gz | |
Fix strictness signatures of `prefetchValue*#` primops
Their strictness signatures said the primops are strict in their first
argument, which is wrong: Handing it a thunk will prefetch the pointer
to the thunk, but not evaluate it. Hence not strict.
The regression test `T8256` actually tests for laziness in the first
argument, so GHC apparently never exploited the strictness signature.
See also https://gitlab.haskell.org/ghc/ghc/-/issues/8256#note_310867,
where this came up.
| -rw-r--r-- | compiler/GHC/Builtin/primops.txt.pp | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/compiler/GHC/Builtin/primops.txt.pp b/compiler/GHC/Builtin/primops.txt.pp index acee822b0c..74abca2927 100644 --- a/compiler/GHC/Builtin/primops.txt.pp +++ b/compiler/GHC/Builtin/primops.txt.pp @@ -3519,8 +3519,7 @@ primop PrefetchAddrOp3 "prefetchAddr3#" GenPrimOp primop PrefetchValueOp3 "prefetchValue3#" GenPrimOp a -> State# s -> State# s - with strictness = { \ _arity -> mkClosedStrictSig [botDmd, topDmd] topDiv } - has_side_effects = True + with has_side_effects = True ---- primop PrefetchByteArrayOp2 "prefetchByteArray2#" GenPrimOp @@ -3537,8 +3536,7 @@ primop PrefetchAddrOp2 "prefetchAddr2#" GenPrimOp primop PrefetchValueOp2 "prefetchValue2#" GenPrimOp a -> State# s -> State# s - with strictness = { \ _arity -> mkClosedStrictSig [botDmd, topDmd] topDiv } - has_side_effects = True + with has_side_effects = True ---- primop PrefetchByteArrayOp1 "prefetchByteArray1#" GenPrimOp @@ -3555,8 +3553,7 @@ primop PrefetchAddrOp1 "prefetchAddr1#" GenPrimOp primop PrefetchValueOp1 "prefetchValue1#" GenPrimOp a -> State# s -> State# s - with strictness = { \ _arity -> mkClosedStrictSig [botDmd, topDmd] topDiv } - has_side_effects = True + with has_side_effects = True ---- primop PrefetchByteArrayOp0 "prefetchByteArray0#" GenPrimOp @@ -3573,8 +3570,7 @@ primop PrefetchAddrOp0 "prefetchAddr0#" GenPrimOp primop PrefetchValueOp0 "prefetchValue0#" GenPrimOp a -> State# s -> State# s - with strictness = { \ _arity -> mkClosedStrictSig [botDmd, topDmd] topDiv } - has_side_effects = True + with has_side_effects = True ------------------------------------------------------------------------ --- --- |