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| author | Bartosz Nitka <niteria@gmail.com> | 2016-07-05 09:42:44 -0700 |
|---|---|---|
| committer | Bartosz Nitka <niteria@gmail.com> | 2016-07-05 09:44:06 -0700 |
| commit | 27fc75b2fea014006964eafe53b3ae17e058d75b (patch) | |
| tree | d02161a3aacb7495564553714a53c43c2aabc03a | |
| parent | 6cedef01e00e95517a546a72592ba6ff07bac605 (diff) | |
| download | haskell-27fc75b2fea014006964eafe53b3ae17e058d75b.tar.gz | |
Document codegen nondeterminism
We don't care about bit-for-bit reproducibility, so
I'm just documenting this as a possible source.
GHC Trac: #4012
| -rw-r--r-- | compiler/stgSyn/CoreToStg.hs | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/compiler/stgSyn/CoreToStg.hs b/compiler/stgSyn/CoreToStg.hs index 273cbdb9c1..2d9ca8cb2a 100644 --- a/compiler/stgSyn/CoreToStg.hs +++ b/compiler/stgSyn/CoreToStg.hs @@ -43,6 +43,7 @@ import DynFlags import ForeignCall import Demand ( isUsedOnce ) import PrimOp ( PrimCall(..) ) +import UniqFM import Data.Maybe (isJust) import Control.Monad (liftM, ap) @@ -1002,7 +1003,10 @@ lookupFVInfo fvs id -- Non-top-level things only, both type variables and ids getFVs :: FreeVarsInfo -> [Var] -getFVs fvs = [id | (id, how_bound, _) <- varEnvElts fvs, +getFVs fvs = [id | (id, how_bound, _) <- nonDetEltsUFM fvs, + -- It's OK to use nonDetEltsUFM here because we're not aiming for + -- bit-for-bit determinism. + -- See Note [Unique Determinism and code generation] not (topLevelBound how_bound) ] getFVSet :: FreeVarsInfo -> VarSet |