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| author | Sebastian Graf <sebastian.graf@kit.edu> | 2021-05-14 12:24:48 +0200 |
|---|---|---|
| committer | Zubin Duggal <zubin.duggal@gmail.com> | 2021-09-21 22:28:27 +0530 |
| commit | 6b64aa7c48d607052e79e3927a4f896b33803086 (patch) | |
| tree | 0056242bc57efa5498a01ad16f8734d9f83b4066 | |
| parent | 55407bf2a451d73e9648a0a5c1b0e4dd7b14e9db (diff) | |
| download | haskell-6b64aa7c48d607052e79e3927a4f896b33803086.tar.gz | |
CPR: Detect constructed products in `runRW#` apps (#19822)
In #19822, we realised that the Simplifier's new habit of floating cases into
`runRW#` continuations inhibits CPR analysis from giving key functions of `text`
the CPR property, such as `singleton`.
This patch fixes that by anticipating part of !5667 (Nested CPR) to give
`runRW#` the proper CPR transformer it now deserves: Namely, `runRW# (\s -> e)`
should have the CPR property iff `e` has it.
The details are in `Note [Simplification of runRW#]` in GHC.CoreToStg.Prep.
The output of T18086 changed a bit: `panic` (which calls `runRW#`) now has
`botCpr`. As outlined in Note [Bottom CPR iff Dead-Ending Divergence], that's
OK.
Fixes #19822.
Metric Decrease:
T9872d
(cherry picked from commit e87b8e108303634af8a7247037d50ab10456c189)
| -rw-r--r-- | compiler/GHC/Core/Opt/CprAnal.hs | 7 | ||||
| -rw-r--r-- | testsuite/tests/cpranal/sigs/T19822.stderr | 2 |
2 files changed, 6 insertions, 3 deletions
diff --git a/compiler/GHC/Core/Opt/CprAnal.hs b/compiler/GHC/Core/Opt/CprAnal.hs index a9902634c2..cdaf4014bb 100644 --- a/compiler/GHC/Core/Opt/CprAnal.hs +++ b/compiler/GHC/Core/Opt/CprAnal.hs @@ -239,9 +239,12 @@ cprTransform env id args sig where sig - -- Top-level binding, local let-binding or case binder + -- Top-level binding, local let-binding, lambda arg or case binder | Just sig <- lookupSigEnv env id - = getCprSig sig + = applyCprTy (getCprSig sig) (length args) + -- CPR transformers for special Ids + | Just cpr_ty <- cprTransformSpecial id args + = cpr_ty -- See Note [CPR for data structures] | Just rhs <- cprDataStructureUnfolding_maybe id = fst $ cprAnal env rhs diff --git a/testsuite/tests/cpranal/sigs/T19822.stderr b/testsuite/tests/cpranal/sigs/T19822.stderr index 5f1522fd00..8e4636d322 100644 --- a/testsuite/tests/cpranal/sigs/T19822.stderr +++ b/testsuite/tests/cpranal/sigs/T19822.stderr @@ -1,5 +1,5 @@ ==================== Cpr signatures ==================== -T19822.singleton: m1 +T19822.singleton: 1 |