I've just committed this patch sequence fb9ae288088a3eabc4e1bb4e86fa473a3881d2e2 Make FloatOut/SetLevels idemoptent on bottoming functions 995ab74b3c55fe3a0299bd94b49e948c942e76d6 Comments only 1163f4f2fe9aabd722c963497c67c5f8c71ef71b Tiny refactor 9b2c73ea8082199245bfa6a28390b70b38f87fd1 Make TH_Roles2 less fragile 9304df5230a7a29d3e992916d133e462b854e55f Fix CSE (again) on literal strings In my final validate run (after updating to HEAD) I saw Unexpected stat failures: perf/compiler/T13035.run T13035 [stat too good] (normal) -6.4% alloc perf/compiler/T12425.run T12425 [stat too good] (optasm) -6.6% alloc perf/compiler/T9675.run T9675 [stat too good] (optasm) -10.4% alloc perf/compiler/T1969.run T1969 [stat too good] (normal) -21% peak megabytes perf/space_leaks/T4029.run T4029 [stat too good] (ghci) -14% peak megabytes This is good. I did not see these in earlier validations (perhaps I did not rebuild the libraries sufficiently), so I have left them. If Harbormaster agrees that perf has improved, could someone re-centre the numbers? Ideally say which patch is responsible. Simon