[GHC] #13745: Investigate compile-time regressions in regex-tdfa-1.2.2
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2
-------------------------------------+-------------------------------------
Reporter: bgamari | Owner: (none)
Type: task | Status: new
Priority: high | Milestone: 8.2.1
Component: Compiler | Version: 8.0.1
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:
-------------------------------------+-------------------------------------
hvr [[https://mail.haskell.org/pipermail/ghc-
devs/2017-May/014208.html|points out]] that GHC 8.2 takes significantly
longer to compile `regex-tdfa-1.2.2` than 8.0.2. Interestingly, it seems
that compiler allocations fell dramatically while compilation time rose.
{{{
GHC 8.0.2:
<
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 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 asr): * cc: asr (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 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 hvr): * cc: hvr (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 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 RyanGlScott): * Attachment "regex-tdfa-reduced.tar.gz" added. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): I've attached a minimized version of `regex-tdfa-1.2.2` with no external dependencies. Moreover, the slowdown in GHC 8.2 seems primarily concentrated at the `*Engine` files, so I only included what was necessary to support one of them. Here are the times that I got: {{{ $ time /opt/ghc/8.0.2/bin/ghc -O2 -fforce-recomp TextRegexTDFANewDFAEngine_FA.hs real 0m10.139s user 0m9.996s sys 0m0.116s $ time /opt/ghc/8.2.1/bin/ghc -O2 -fforce-recomp TextRegexTDFANewDFAEngine_FA.hs real 0m18.072s user 0m17.912s sys 0m0.156s }}} The `TextRegexTDFANewDFAEngine_FA.hs` file in particular is what is contributing to the difference in time, as all other modules take about the same time to compile on 8.0.2 and 8.2.1-rc2. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 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 RyanGlScott): * cc: simonpj (added) Comment: A sizeable chunk of that increase in time came from commit 2effe18ab51d66474724d38b20e49cc1b8738f60 (The Early Inline Patch): {{{ Commit 55efc9718b520ef354e32c15c4b49cdfecce412f (Combine identical case alternatives in CSE) ----- real 0m10.682s user 0m10.392s sys 0m0.272s Commit 2effe18ab51d66474724d38b20e49cc1b8738f60 (The Early Inline Patch) ----- real 0m13.742s user 0m13.524s sys 0m0.204s }}} What's responsible for the other ~5 seconds remains to be investigated. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): Found it. The other culprit is commit 6eb52cfc2e31df2561860f43d41766464ccfe8af (Improve SetLevels for join points): {{{ Commit 871b63e4ea95d4c516d31378d0475167e75caa01 (Improve pretty-printing of types) ----- real 0m13.918s user 0m13.708s sys 0m0.192s Commit 6eb52cfc2e31df2561860f43d41766464ccfe8af (Improve SetLevels for join points) ----- real 0m19.008s user 0m18.804s sys 0m0.188s }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 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 michalt): * cc: michalt (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.0.1 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 bgamari): * milestone: 8.2.1 => 8.2.2 Comment: This is certainly a significant regression, but I think it will need to wait until 8.2.2 at the earliest for resolution. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by dfeuer): Going from 8.0.2 to 8.2.1, things look very different right near the beginning, presumably as a result of the early inline patch. In 8.0.2, the first simplifier pass gives {{{ *** Simplifier [TextRegexTDFANewDFAEngine_FA]: Result size of Simplifier iteration=1 = {terms: 6,220, types: 14,606, coercions: 1,563} }}} whereas in 8.2.1 it gives {{{ *** Simplifier [TextRegexTDFANewDFAEngine_FA]: Result size of Simplifier iteration=1 = {terms: 17,641, types: 38,397, coercions: 10,258, joins: 30/233} }}} Things remain pretty bad until after float out, when they first get surprisingly good and then sort of oscillate. I'll take a look at the differences across the commits Ryan points out. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by dfeuer): In "Improve SetLevels for join points", everything is fine until liberate case. With the previous commit, this produces 34,318 terms, 54,571 types, 3,409 coercions, and 456/760 joins. With the SetLevels commit, this goes up to 57,468 terms, 83,821 types, 3,439 coercions, and 856/1,310 joins. It never makes up for that. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by bgamari): Hmm, it may be helpful to see what the additional bindings look like. This is when I would usually use my [[https://github.com/bgamari/ghc-dump|ghc- dump]] utility to dump a summary of the top-level bindings and their types. This should be easily diffable. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by dfeuer): Replying to [comment:10 bgamari]:
Hmm, it may be helpful to see what the additional bindings look like. This is when I would usually use my [[https://github.com/bgamari/ghc-dump |ghc-dump]] utility to dump a summary of the top-level bindings and their types. This should be easily diffable.
Unfortunately, this seems ... challenging. I'm running the "before" version now. It's been going for many minutes, and is really chewing up disk space. In particular, `TextRegexTDFANewDFAEngine_FA.pass-0017.cbor` has already passed five gigabytes. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by dfeuer): I was able to get enough to compare the results of `LiberateCase`. Things generally look the same at the top level, but after the `SetLevels` patch there's a bunch more local code. Everything is rather huge, so it's hard to see just what the deal is, but interestingly it really seems to be ''added'' code more than ''replaced'' code. Virtually everything that used to be there is still there, but now there's more. I'll attach diffable dump files. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:12 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.0.1 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 dfeuer): * Attachment "pre-set-levels.gz" added. Before setlevels patch -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.0.1 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 dfeuer): * Attachment "post-set-levels.bz2" added. After setlevels patch -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.0.1 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 dfeuer): * cc: dfeuer (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.3 Component: Compiler | Version: 8.0.1 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 bgamari): * milestone: 8.2.2 => 8.2.3 Comment: It doesn't look like this is going to happen for 8.2.2. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.3 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by rahulmutt): I recently merged the DmdAnal module from ghc master into Eta and observed a 2-3x blowup in generated codesize for the exact same module - Text.Regex.TDFA.NewDFA.Engine_FA. Given that the Eta code base does not yet contain the early inlining patch or anything relating to join points, I think one thing to be looking at is the impact of the new changes to the demand analyzer and how the inliner reacts to strictness/usage information. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.3 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by bgamari): rahulmutt, thanks for the datapoint. Can you say more specifically which revision of `DmdAnal` you were previously using and which you updated to? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.3 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by rahulmutt): Before: 63205f719287cb011388b4beddf30d3229238b9f (DmdAnal in ghc-7.10.3a- release tag) After: b5b7d820afd8fca098bf1f4a7380d425ca6be31d I still need to merge in the recent occurrence analyzer changes since I recall reading that OneShotInfo is not longer handled in the demand analyzer and has moved to the occurence analyzer. Nonetheless, I don't think lack of OneShotInfo would cause the observed magnitude of code size difference, but I may be wrong. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:17 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.3 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by ntc2): I'm observing an apparently **exponential run time performance regression** when combining GHC 8.2.1, `Data.Text.Lazy`, and `Text.RE.TDFA`. Here's my repo with simple test code illustrating the regression and timing stats: https://github.com/ntc2/ghc-8.2.1-regex-lazy- text-bug. In summary, for the problematic combination of GHC version and libraries, the run times are 3s, 10s, 22s, and 40s for counting regex matches in files with 10000, 20000, 30000, and 40000 lines, respectively. For all of the unproblematic combinations -- i.e. GHC 8.0.2, `String`, strict `Data.Text`, or building with profiling -- the run time is always about 1s! And this is a Heisenbug, in that the performance problem goes away if I build with profiling support! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:18 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.3 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by nomeata): @ntc2, that is an interesting finding, but maybe worth a separate issue. Since you seem to have a nice setup to verify the problem, could you bisect which commit in GHC did this? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.3 Component: Compiler | Version: 8.0.1 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 ntc2): * cc: ntc2 (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:20 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.3 Component: Compiler | Version: 8.0.1 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: | -------------------------------------+------------------------------------- Comment (by ntc2): @nomeata, I'll create a separate issue and try the bisection. Never done Git bisection before, but found a GHC docs page here: https://ghc.haskell.org/trac/ghc/wiki/WorkingConventions/Bisection. (also, I thought commenting added me to the CC list, but apparently not) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:21 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#13745: Investigate compile-time regressions in regex-tdfa-1.2.2 -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: high | Milestone: 8.2.3 Component: Compiler | Version: 8.0.1 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 gbaz): * cc: gbaz (added) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13745#comment:22 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
participants (1)
-
GHC