id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
3234,foldr/single no longer firing in GHC 6.10,r6,,"consider the following module

{{{module Foo where x = ['x']++""haskell""}}}

when {{{ghc --make -O2 Foo.hs -ddump-simpl-stats}}}  is run using GHC 6.8.2, the output show that the foldr/single rule is fired

{{{
5 RuleFired
    1 ++
    1 augment/build
    1 foldr/single
    1 unpack
    1 unpack-list
}}}

However, I am told that this does not happen in GHC 6.10.2 nor GHC 6.10.3 where foldr/app is fired instead

{{{
6 RuleFired
     1 ++
     1 augment/build
     1 fold/build
     1 foldr/app
     1 unpack
     1 unpack-list
}}}

Thus it appears that the above module is no longer properly optimized in GHC 6.10

(thanks to dons and Jedai for helping with this)",bug,closed,normal,6.12.1,Compiler,6.10.3,fixed,,,Unknown/Multiple,Unknown/Multiple,,Unknown,simplCore/should_compile/T3234,,,