#11095: -O0 -g slows GHC down on list literals (compared to -O0 without -g) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by slyfox): * failure: None/Unknown => Compile-time performance bug Comment: Result on "prof" flavour of ghc-HEAD build with '''-auto-all''' enabled: {{{ Sun Nov 15 16:31 2015 Time and Allocation Profiling Report (Final) ghc-stage2 +RTS -p -RTS -B/home/slyfox/dev/git/ghc- prof/inplace/lib -hide-all-packages -c -g Bug.hs total time = 304.82 secs (304823 ticks @ 1000 us, 1 processor) total alloc = 286,040,926,256 bytes (excludes profiling overheads) COST CENTRE MODULE %time %alloc containsSpan SrcLoc 32.1 55.2 bindIO.\ GHC.Base 10.6 0.0 == FastString 7.7 13.8 tickishContains CoreSyn 6.5 0.0 mkTick.mkTick' CoreUtils 6.4 6.9 eqString GHC.Base 5.9 0.0 <= GHC.Classes 4.4 0.0 srcSpanStartLine SrcLoc 4.4 9.2 uniq FastString 3.8 9.2 compareInt GHC.Classes 3.6 0.0 srcSpanFile SrcLoc 3.0 0.0 srcSpanEndLine SrcLoc 2.3 4.6
= GHC.Classes 1.5 0.0 && GHC.Classes 1.4 0.0 == GHC.Classes 1.2 0.0 /= CoreSyn 1.1 0.0
... mapOL OrdList 154083 917328 0.0 0.0 88.9 99.6 wrapTicks.wrap CorePrep 154085 915975 0.0 0.0 88.9 99.6 wrapTicks.wrapBind CorePrep 154086 915975 0.0 0.1 88.9 99.6 mkTick CoreUtils 154087 915975 1.0 0.0 88.8 99.5 mkTick.canSplit CoreUtils 154113 915975 0.0 0.0 0.0 0.0 && GHC.Classes 154115 915975 0.0 0.0 0.0 0.0 tickishCanSplit CoreSyn 154114 915975 0.0 0.0 0.0 0.0 mkTick.mkTick' CoreUtils 154088 411894225 6.4 6.9 87.8 99.5 tickishContains CoreSyn 154120 821043225 6.5 0.0 78.6 92.5 containsSpan SrcLoc 154125 821037825 32.0 55.1 64.3 92.5 ... }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11095#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler