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| author | simonpj@microsoft.com <unknown> | 2008-01-17 15:03:25 +0000 |
|---|---|---|
| committer | simonpj@microsoft.com <unknown> | 2008-01-17 15:03:25 +0000 |
| commit | 44d4bf2c3eff873d18e683c0629f17a228e9dfe0 (patch) | |
| tree | 462a4571ab30f5c4b9d3d41fae4107629a21c2f6 /compiler/main/StaticFlags.hs | |
| parent | 448873c017b64b4343f695925b4470fa21e216f5 (diff) | |
| download | haskell-44d4bf2c3eff873d18e683c0629f17a228e9dfe0.tar.gz | |
Add -fspec-inline-join-points to SpecConstr
This patch addresses a problem that Roman found in SpecConstr. Consider:
foo :: Maybe Int -> Maybe Int -> Int
foo a b = let j b = foo a b
in
case b of
Nothing -> ...
Just n -> case a of
Just m -> ... j (Just (n+1)) ...
Nothing -> ... j (Just (n-1)) ...
We want to make specialised versions for 'foo' for the patterns
Nothing (Just v)
(Just a) (Just b)
Two problems, caused by the join point j. First, j does not
scrutinise b, so j won't be specialised f for the (Just v) pattern.
Second, j is defined where the free var 'a' is not evaluated.
Both are solved by brutally inlining j at its call sites. This risks
major code bloat, but it's relatively quick to implement. The flag
-fspec-inline-join-points
causes brutal inlining for a
non-recursive binding
of a function
whose RHS contains calls
of a recursive function
The (experimental) flag is static for now, and I have not even
documented it properly.
Diffstat (limited to 'compiler/main/StaticFlags.hs')
| -rw-r--r-- | compiler/main/StaticFlags.hs | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/compiler/main/StaticFlags.hs b/compiler/main/StaticFlags.hs index 59e125c82d..f245d18f0e 100644 --- a/compiler/main/StaticFlags.hs +++ b/compiler/main/StaticFlags.hs @@ -49,6 +49,7 @@ module StaticFlags ( -- optimisation opts opt_NoMethodSharing, opt_NoStateHack, + opt_SpecInlineJoinPoints, opt_CprOff, opt_SimplNoPreInlining, opt_SimplExcessPrecision, @@ -303,6 +304,7 @@ opt_Parallel = lookUp FSLIT("-fparallel") opt_Flatten = lookUp FSLIT("-fflatten") -- optimisation opts +opt_SpecInlineJoinPoints = lookUp FSLIT("-fspec-inline-join-points") opt_NoStateHack = lookUp FSLIT("-fno-state-hack") opt_NoMethodSharing = lookUp FSLIT("-fno-method-sharing") opt_CprOff = lookUp FSLIT("-fcpr-off") @@ -362,6 +364,7 @@ isStaticFlag f = "fauto-sccs-on-individual-cafs", "fscc-profiling", "fdicts-strict", + "fspec-inline-join-points", "firrefutable-tuples", "fparallel", "fflatten", |