[GHC] #13745: Investigate compile-time regressions in regex-tdfa-1.2.2

[GHC]

#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