#7206: Implement cheap build ---------------------------------+------------------------------------------ Reporter: simonpj | Owner: simonpj Type: bug | Status: new Priority: normal | Milestone: _|_ Component: Compiler | Version: 7.4.2 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: None/Unknown Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | ---------------------------------+------------------------------------------ Changes (by simonpj): * milestone: 7.8.1 => _|_ Comment: I tried this again, but got disappointing results: {{{ -------------------------------------------------------------------------------- Program Size Allocs Runtime Elapsed TotalMem -------------------------------------------------------------------------------- anna -0.4% +0.0% -6.3% -5.9% +0.0% ansi -0.2% -0.6% 0.00 0.00 +0.0% atom -0.1% +0.0% +2.0% +2.0% +0.0% awards -0.4% +0.0% 0.00 0.00 +0.0% banner -0.1% +0.0% 0.00 0.00 +0.0% bernouilli -0.0% +0.0% -1.6% -1.6% +0.0% binary-trees -0.2% +0.0% +4.4% +4.4% +0.0% boyer -0.2% +0.0% 0.07 0.07 +0.0% boyer2 -0.5% +0.0% 0.01 0.01 +0.0% bspt -0.3% +0.0% 0.02 0.02 +0.0% cacheprof -1.4% +0.2% -0.7% -0.9% -0.5% calendar -0.2% +0.0% 0.00 0.00 +0.0% cichelli -0.4% -0.0% 0.13 0.13 +0.0% circsim -0.2% +0.0% -4.6% -4.7% +0.0% clausify -0.2% +0.0% 0.06 0.06 +0.0% comp_lab_zift -0.2% +0.0% -2.6% -2.6% +0.0% compress -0.3% +0.0% +3.0% +3.7% +0.0% compress2 -0.1% +0.0% +1.3% +1.3% +0.0% constraints -0.2% +0.0% -3.9% -3.9% +0.0% cryptarithm1 -0.2% +0.0% +6.3% +6.3% +0.0% cryptarithm2 -0.5% +0.0% 0.02 0.02 +0.0% cse -0.5% +0.0% 0.00 0.00 +0.0% eliza -0.1% +0.0% 0.00 0.00 +0.0% event -0.2% +0.0% +2.9% +2.9% +0.0% exp3_8 -0.2% +0.0% -2.8% -2.8% +0.0% expert -0.1% +0.0% 0.00 0.00 +0.0% fannkuch-redux -0.1% +0.0% -2.4% -2.4% +0.0% fasta -0.2% +0.0% -0.4% -0.4% +0.0% fem -0.0% +0.0% 0.04 0.04 +0.0% fft -0.1% +0.0% 0.06 0.06 +0.0% fft2 -0.1% +0.0% 0.10 0.10 +0.0% fibheaps -0.2% +0.0% 0.05 0.05 +0.0% fish -0.1% +2.7% 0.03 0.03 +0.0% fluid -0.1% +0.2% 0.01 0.01 +100.0% fulsom -0.3% +0.0% -4.0% -4.0% +3.2% gamteb -0.1% -0.0% 0.07 0.07 +0.0% gcd -0.1% +0.0% 0.05 0.05 +0.0% gen_regexps -0.1% +0.0% 0.00 0.00 +0.0% genfft -0.1% +0.0% 0.06 0.06 +0.0% gg -0.5% +0.1% 0.02 0.02 +0.0% grep -0.1% +0.0% 0.00 0.00 +0.0% hidden -0.1% +0.0% +4.2% +4.2% +0.0% hpg -0.4% -0.2% +8.8% +8.8% +0.0% ida -0.2% +0.0% 0.14 0.14 +0.0% infer -0.3% +0.0% 0.13 0.13 +0.0% integer -0.1% +0.0% +0.1% +0.1% +0.0% integrate -0.1% +0.0% +18.2% +18.2% +0.0% k-nucleotide -0.1% +0.0% -6.2% -6.2% +0.0% kahan -0.1% +0.0% +1.1% +1.1% +0.0% knights -0.2% +1.4% 0.01 0.01 +0.0% lcss -0.2% +0.0% -3.5% -3.5% +0.0% life -0.2% +0.0% +2.5% +2.5% +0.0% lift -0.3% +0.0% 0.00 0.00 +0.0% listcompr -0.2% +0.0% 0.15 0.15 +0.0% listcopy -0.2% +0.0% 0.16 0.16 +0.0% maillist -0.3% +0.0% 0.10 0.11 -3.9% mandel -0.0% -0.0% 0.12 0.12 +0.0% mandel2 -0.5% +0.0% 0.00 0.00 +0.0% minimax -0.3% +0.0% 0.00 0.00 +0.0% mkhprog -0.2% +0.0% 0.00 0.00 +0.0% multiplier -0.3% +0.0% +1.8% +1.8% +0.0% n-body -0.2% +0.0% -0.7% -0.6% +0.0% nucleic2 -0.1% +0.0% 0.11 0.11 +0.0% para -0.0% +0.0% +1.4% +0.8% +0.0% paraffins -0.2% +0.0% +13.6% +13.6% +0.0% parser -1.3% +3.5% 0.05 0.05 +0.0% parstof -0.3% +0.0% 0.01 0.01 +0.0% pic -0.1% +0.1% 0.00 0.00 +0.0% pidigits -0.1% +0.0% +1.5% +1.9% +0.0% power -0.1% +0.0% -4.9% -4.9% +0.0% pretty -0.1% -0.0% 0.00 0.00 +0.0% primes -0.1% +0.0% 0.11 0.11 +0.0% primetest -0.0% +0.0% 0.14 0.14 +0.0% prolog -0.2% +0.1% 0.00 0.17 +0.0% puzzle -0.3% +0.0% +1.7% +1.7% +0.0% queens -0.2% +0.0% 0.02 0.02 +0.0% reptile -0.2% -0.0% 0.02 0.02 +0.0% reverse-complem -0.3% +0.0% +3.8% +3.8% +0.0% rewrite -0.2% +0.0% 0.02 0.02 +0.0% rfib -0.1% +0.0% 0.03 0.03 +0.0% rsa -0.0% +0.0% 0.03 0.12 +0.0% scc -0.2% +0.0% 0.00 0.00 +0.0% sched -0.2% +0.0% 0.03 0.03 +0.0% scs -0.0% +0.1% -2.9% -3.1% +0.0% simple -0.9% +0.6% -10.8% -10.8% +13.8% solid -0.1% +0.0% +3.2% +3.2% +0.0% sorting -0.1% +0.0% 0.00 0.00 +0.0% spectral-norm -0.2% +0.0% +0.1% +0.1% +0.0% sphere -0.2% +0.0% 0.08 0.08 +0.0% symalg -0.2% +0.0% 0.01 0.04 +0.0% tak -0.2% +0.0% 0.02 0.02 +0.0% transform -0.2% +0.0% -0.6% -0.6% +0.0% treejoin -0.2% +0.0% +0.0% -0.7% +0.0% typecheck -0.2% -0.0% +0.0% +0.0% +0.0% veritas +0.7% +0.0% 0.00 0.00 +0.0% wang -0.1% +0.0% -5.5% -5.5% +0.0% wave4main -0.2% +0.0% -2.4% -2.4% +0.0% wheel-sieve1 -0.1% +0.0% -0.5% -0.5% +0.0% wheel-sieve2 -0.1% +0.0% -6.4% -6.4% +0.0% x2n1 -0.2% +0.0% 0.00 0.00 +0.0% -------------------------------------------------------------------------------- Min -1.4% -0.6% -10.8% -10.8% -3.9% Max +0.7% +3.5% +18.2% +18.2% +100.0% Geometric Mean -0.2% +0.1% +0.1% +0.1% +0.8% }}} On investigation it seemed that although it was good to fuse away the intermediate ''lists'', we were duplicating the individual `Int`s or `Char`s that would otherwise have been shared, and this pushes up allocation. So we often lose a bit and seldom win much. So I'm parking this again. I attach the patches I used. Simon -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7206#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler