diff options
| author | Matthew Pickering <matthewtpickering@gmail.com> | 2021-09-14 15:23:51 +0100 |
|---|---|---|
| committer | Zubin Duggal <zubin.duggal@gmail.com> | 2021-10-12 14:54:34 +0530 |
| commit | a54e54fa4b121c0210f55e5d6e338d7af6e6922b (patch) | |
| tree | 77761630e0eec64da33b7d104d9c70f8cf352481 | |
| parent | 49acdc6d5695e02ebd56ce2f4a3b58086b33963a (diff) | |
| download | haskell-a54e54fa4b121c0210f55e5d6e338d7af6e6922b.tar.gz | |
Code Gen: Use strict map rather than lazy map in loop analysis
We were ending up with a big 1GB thunk spike as the `fmap` operation did
not force the key values promptly.
This fixes the high maximum memory consumption when compiling the mmark
package. Compilation is still slow and allocates a lot more than
previous releases.
Related to #19471
(cherry picked from commit 9eff805a622db499be1fda304e11bb3e6c8d37f0)
| -rw-r--r-- | compiler/GHC/CmmToAsm/CFG.hs | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/compiler/GHC/CmmToAsm/CFG.hs b/compiler/GHC/CmmToAsm/CFG.hs index 5db10ce93f..63b488d482 100644 --- a/compiler/GHC/CmmToAsm/CFG.hs +++ b/compiler/GHC/CmmToAsm/CFG.hs @@ -307,7 +307,9 @@ shortcutWeightMap cuts cfg = applyMapping m (from, Just to) = let updatedMap :: CFG updatedMap - = fmap (shortcutEdge (from,to)) $ + -- Careful here to use a strict mapping function, the derived + -- Functor instance is lazy and leads to a large thunk build-up. #19471/!6523 + = mapMap (shortcutEdge (from,to)) $ (mapDelete from m :: CFG ) --Sometimes we can shortcut multiple blocks like so: -- A -> B -> C -> D -> E => A -> E |