#9374: Investigate Static Argument Transformation -------------------------------------+------------------------------------- Reporter: jstolarek | Owner: Type: task | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 7.9 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Unknown Type of failure: | Blocked By: None/Unknown | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by simonpj): Here's an example where SAT would be a big win. See [http://www.haskell.org/pipermail/ghc-devs/2014-September/006332.html email thread]. {{{ scanr = \ @ a_akP @ a1_akQ f_ah8 b_ah9 eta_B1 -> letrec { go_amb go_amb = \ ds_amc eta1_Xa eta2_B2 eta3_Xc -> case ds_amc of _ { [] -> eta1_Xa eta2_B2 eta3_Xc; : y_amh ys_ami -> go_amb ys_ami (\ x_an9 eta4_Xj -> let { b'_ana b'_ana = f_ah8 y_amh x_an9 } in eta1_Xa b'_ana (: b'_ana eta4_Xj)) eta2_B2 eta3_Xc }; } in go_amb eta_B1 scanr1 b_ah9 (: b_ah9 ([])) }}} The 3rd and 4th arg to `go` are static, and since there is only one call to `go`, doing SAT would yield much better code by specialising `go` for the particular parameters: {{{ scanr = \ @ a_akP @ a1_akQ f_ah8 b_ah9 eta_B1 -> let { listend listend = : b_ah9 ([])} in letrec { go_amb go_amb = \ ds_amc eta1_Xa -> case ds_amc of _ { [] -> eta1_Xa b_ah9 listend; : y_amh ys_ami -> go_amb ys_ami (\ x_an9 eta4_Xj -> let { b'_ana b'_ana = f_ah8 y_amh x_an9 } in eta1_Xa b'_ana (: b'_ana eta4_Xj)) }; } in go_amb eta_B1 scanr1 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9374#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler