[GHC] #15524: Performance regression when using the GHC API to evaluate code compared to 8.4

[GHC]

#15524: Performance regression when using the GHC API to evaluate code compared to
8.4
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        Reporter:  vaibhavsagar      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.6.1-beta1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Old description:

> I've been in the process of updating IHaskell to support GHC 8.6 and the
> test suite has become agonisingly slow as compared to GHC 8.4 and below.
> I've been able to work around this by using `--enable-executable-dynamic`
> as suggested by `christiaanb` on `#ghc`but I thought this was worth
> reporting as a bug. I am using `ghc-8.6.1-alpha2` so it's possible that
> this has been fixed in `beta1`.
>
> To reproduce this on a Linux installation with Nix:
>
> 1. `git clone https://github.com/gibiansky/IHaskell --branch support-
> ghc-8-6 repro`
> 2. `cd repro`
> 3. Comment out `--enable-executable-dynamic` in `release-8.6.nix`
> 4. `nix-build release-8.6.nix`

New description:

 I've been in the process of updating IHaskell to support GHC 8.6 and the
 test suite has become agonisingly slow as compared to GHC 8.4 and below.
 I've been able to work around this by using `--enable-executable-dynamic`
 as suggested by `christiaanb` on `#ghc`but I thought this was worth
 reporting as a bug.

 To reproduce this on a Linux installation with Nix:

 1. `git clone https://github.com/gibiansky/IHaskell --branch support-
 ghc-8-6 repro`
 2. `cd repro`
 3. Comment out `--enable-executable-dynamic` in `release-8.6.nix`
 4. `nix-build release-8.6.nix`

--

Comment (by vaibhavsagar):

 I've since tried this with GHC 8.6.1-beta1 and am seeing the same
 behaviour.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15524#comment:2>
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