diff options
Diffstat (limited to 'compiler/GHC/Core/Opt/Simplify.hs')
| -rw-r--r-- | compiler/GHC/Core/Opt/Simplify.hs | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/compiler/GHC/Core/Opt/Simplify.hs b/compiler/GHC/Core/Opt/Simplify.hs index da039a8e83..13f0fdc46c 100644 --- a/compiler/GHC/Core/Opt/Simplify.hs +++ b/compiler/GHC/Core/Opt/Simplify.hs @@ -3996,14 +3996,17 @@ simplRules env mb_new_id rules mb_cont = return rule simpl_rule rule@(Rule { ru_bndrs = bndrs, ru_args = args - , ru_fn = fn_name, ru_rhs = rhs }) + , ru_fn = fn_name, ru_rhs = rhs + , ru_act = act }) = do { (env', bndrs') <- simplBinders env bndrs ; let rhs_ty = substTy env' (exprType rhs) rhs_cont = case mb_cont of -- See Note [Rules and unfolding for join points] Nothing -> mkBoringStop rhs_ty Just cont -> ASSERT2( join_ok, bad_join_msg ) cont - rule_env = updMode updModeForRules env' + lhs_env = updMode updModeForRules env' + rhs_env = updMode (updModeForStableUnfoldings act) env' + -- See Note [Simplifying the RHS of a RULE] fn_name' = case mb_new_id of Just id -> idName id Nothing -> fn_name @@ -4018,9 +4021,18 @@ simplRules env mb_new_id rules mb_cont bad_join_msg = vcat [ ppr mb_new_id, ppr rule , ppr (fmap isJoinId_maybe mb_new_id) ] - ; args' <- mapM (simplExpr rule_env) args - ; rhs' <- simplExprC rule_env rhs rhs_cont + ; args' <- mapM (simplExpr lhs_env) args + ; rhs' <- simplExprC rhs_env rhs rhs_cont ; return (rule { ru_bndrs = bndrs' , ru_fn = fn_name' , ru_args = args' , ru_rhs = rhs' }) } + +{- Note [Simplifying the RHS of a RULE] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +We can simplify the RHS of a RULE much as we do the RHS of a stable +unfolding. We used to use the much more conservative updModeForRules +for the RHS as well as the LHS, but that seems more conservative +than necesary. Allowing some inlining might, for example, eliminate +a binding. +-}
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