diff options
Diffstat (limited to 'compiler/simplCore/SimplCore.hs')
| -rw-r--r-- | compiler/simplCore/SimplCore.hs | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/compiler/simplCore/SimplCore.hs b/compiler/simplCore/SimplCore.hs index 0fd929a2a6..38ba186e8a 100644 --- a/compiler/simplCore/SimplCore.hs +++ b/compiler/simplCore/SimplCore.hs @@ -179,9 +179,11 @@ getCoreToDo dflags , sm_names = ["Gentle"] , sm_rules = rules_on -- Note [RULEs enabled in SimplGently] , sm_inline = False - , sm_case_case = False }) - -- Don't do case-of-case transformations. - -- This makes full laziness work better + , sm_case_case = False + -- Don't do case-of-case transformations. + -- This makes full laziness work better + , sm_eta_expand = False}) + -- Note [Do not eta-expand in SimplGently] -- New demand analyser demand_analyser = (CoreDoPasses ([ @@ -946,3 +948,14 @@ transferIdInfo exported_id local_id (specInfo local_info) -- Remember to set the function-name field of the -- rules as we transfer them from one function to another + +-- Note [Do not eta-expand in SimplGently] +-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +-- +-- Eta-expansion can seriously blow up the size of the code, if there are +-- newtypes and coercions involved; see #9020 for a particularly good example. +-- +-- It may work out well in a full simplifier phase, when the additional +-- coercions can be optimized away, e.g. after inlining. But the gentle phase +-- does less, in particular no inlining, so chances are high that we will blow +-- up our code for on good reason. |