#10491: Regression, simplifier explosion with Accelerate, cannot compile,
increasing tick factor is not a workaround
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Reporter: robertce | Owner:
Type: bug | Status: new
Priority: highest | Milestone: 7.10.2
Component: Compiler | Version: 7.10.1
Resolution: | Keywords:
Operating System: Unknown/Multiple | Architecture:
Type of failure: Compile-time | Unknown/Multiple
performance bug | Test Case:
Blocked By: | Blocking:
Related Tickets: | Differential Revisions:
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Comment (by bgamari):
George, what GHC version did you test `-fno-specialise` on? While
yesterday I was able to confirm that `-fno-specialise` seemed to make no
difference on a test machine running what should have been 7.10.1 I am now
having trouble replicating this on my laptop. Unfortunately I no longer
have access to the test environment on which I tested this yesterday but
clearly something was inconsistent.
I am now seeing on multiple machines that `-fno-specialise` indeed allows
things to compile,
{{{
$ ghc -V
The Glorious Glasgow Haskell Compilation System, version 7.10.1
$$ time ghc Slice.hs -fforce-recomp -O2 -fno-specialise
[1 of 1] Compiling Slice ( Slice.hs, Slice.o )
real 0m3.759s
user 0m1.688s
sys 0m0.044s
$ time ghc Slice.hs -fforce-recomp -O2
[1 of 1] Compiling Slice ( Slice.hs, Slice.o )
^C
real 0m51.103s
user 0m44.336s
sys 0m0.948s
}}}
I am now looking at whether disabling only cross-module specialisation is
enough to eliminate the blow-up.
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10491#comment:27>