On 9/21/07, Victor Nazarov <[EMAIL PROTECTED]> wrote:
> Here is some more details:
>
> % ghc -c -ddump-stg T1.hs
>
> ==================== STG syntax: ====================
> T1.map =
> \u []
> let {
> map1_sdR =
> \r [f_sdN ds_sdI]
> case ds_sdI of wild_sdU {
> [] -> [] [];
> : x_sdM xs_sdQ ->
> let { sat_sdT = \u [] map1_sdR f_sdN xs_sdQ; } in
> let { sat_sdP = \u [] f_sdN x_sdM; } in : [sat_sdP
> sat_sdT];
> };
> } in map1_sdR;
> SRT(T1.map): []
>
>
> % ghc -c -ddump-stg T1.hs -O
>
> ==================== STG syntax: ====================
> T1.map =
> \r [f_sel ds_seg]
> case ds_seg of wild_ser {
> [] -> [] [];
> : x_sek xs_seo ->
> let { sat_seq = \u [] T1.map f_sel xs_seo; } in
> let { sat_sen = \u [] f_sel x_sek; } in : [sat_sen sat_seq];
> };
> SRT(T1.map): []
Sure, it makes sense that the extra thunk would be allocated when
optimization is disabled (if you don't pass in any optimization flags
like -O, it's like saying "don't do any optimization"). Don't expect
GHC to generate efficient code with optimization turned off :-)
Cheers,
Tim
--
Tim Chevalier * catamorphism.org * Often in error, never in doubt
"Other than to amuse himself, why should a man pretend to know where
he's going or to understand what he sees?" -- William Least Heat Moon
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