diff options
Diffstat (limited to 'ghc/compiler')
| -rw-r--r-- | ghc/compiler/coreSyn/CoreUnfold.lhs | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/ghc/compiler/coreSyn/CoreUnfold.lhs b/ghc/compiler/coreSyn/CoreUnfold.lhs index 36a6746567..e254958625 100644 --- a/ghc/compiler/coreSyn/CoreUnfold.lhs +++ b/ghc/compiler/coreSyn/CoreUnfold.lhs @@ -45,7 +45,8 @@ import Bag ( emptyBag, unitBag, unionBags, Bag ) import CmdLineOpts ( opt_UnfoldingCreationThreshold, opt_UnfoldingUseThreshold, - opt_UnfoldingConDiscount + opt_UnfoldingConDiscount, + opt_UnfoldingKeenessFactor ) import Constants ( uNFOLDING_CHEAP_OP_COST, uNFOLDING_DEAR_OP_COST, @@ -482,13 +483,21 @@ smallEnoughToInline _ _ UnfoldNever = False smallEnoughToInline arg_is_evald_s result_is_scruted (UnfoldIfGoodArgs m_tys_wanted n_vals_wanted discount_vec size scrut_discount) = enough_args n_vals_wanted arg_is_evald_s && - discounted_size <= opt_UnfoldingUseThreshold + size - discount <= opt_UnfoldingUseThreshold where enough_args n [] | n > 0 = False -- A function with no value args => don't unfold enough_args _ _ = True -- Otherwise it's ok to try - discounted_size = (size - args_discount) - result_discount + -- We multiple the raw discounts (args_discount and result_discount) + -- ty opt_UnfoldingKeenessFactor because the former have to do with + -- *size* whereas the discounts imply that there's some extra *efficiency* + -- to be gained (e.g. beta reductions, case reductions) by inlining. + discount :: Int + discount = round ( + opt_UnfoldingKeenessFactor * + fromInt (args_discount + result_discount) + ) args_discount = sum (zipWith arg_discount discount_vec arg_is_evald_s) result_discount | result_is_scruted = scrut_discount |