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authorMatthew Pickering <matthewtpickering@gmail.com>2022-02-11 18:07:28 +0000
committerMarge Bot <ben+marge-bot@smart-cactus.org>2022-02-26 02:06:51 -0500
commit2be7446089de644048466ab8e9c71c596fa82d09 (patch)
tree97a0a67f8abc5f023aad79cb3addd5f18a8f2341 /testsuite/tests
parent61a203ba2e942b39c5f26a7ad01017841937fd0a (diff)
downloadhaskell-2be7446089de644048466ab8e9c71c596fa82d09.tar.gz
Use a more up-to-date snapshot of the current rules in the simplifier
As the prescient (now deleted) note warns in simplifyPgmIO we have to be a bit careful about when we gather rules from the EPS so that we get the rules for imported bindings. ``` -- Get any new rules, and extend the rule base -- See Note [Overall plumbing for rules] in GHC.Core.Rules -- We need to do this regularly, because simplification can -- poke on IdInfo thunks, which in turn brings in new rules -- behind the scenes. Otherwise there's a danger we'll simply -- miss the rules for Ids hidden inside imported inlinings ``` Given the previous commit, the loading of unfoldings is now even more delayed so we need to be more careful to read the EPS rule base closer to the point where we decide to try rules. Without this fix GHC performance regressed by a noticeably amount because the `zip` rule was not brought into scope eagerly enough which led to a further series of unfortunate events in the simplifer which tipped `substTyWithCoVars` over the edge of the size threshold, stopped it being inlined and increased allocations by 10% in some cases. Furthermore, this change is noticeably in the testsuite as it changes T19790 so that the `length` rules from GHC.List fires earlier. ------------------------- Metric Increase: T9961 -------------------------
Diffstat (limited to 'testsuite/tests')
-rw-r--r--testsuite/tests/simplCore/should_compile/T19790.stderr2
1 files changed, 1 insertions, 1 deletions
diff --git a/testsuite/tests/simplCore/should_compile/T19790.stderr b/testsuite/tests/simplCore/should_compile/T19790.stderr
index 71632231f7..2108b82afe 100644
--- a/testsuite/tests/simplCore/should_compile/T19790.stderr
+++ b/testsuite/tests/simplCore/should_compile/T19790.stderr
@@ -1,7 +1,7 @@
Rule fired: Class op + (BUILTIN)
Rule fired: Class op length (BUILTIN)
+Rule fired: length (GHC.List)
Rule fired: map (GHC.Base)
Rule fired: fold/build (GHC.Base)
Rule fired: This rule should fire! (T19790)
-Rule fired: length (GHC.List)
Rule fired: lengthList (GHC.List)