Regression T2497 WAY=optasm: Simplifier ticks exhausted

$ make TEST=T2497 WAY=optasm EXTRA_HC_OPTS=-fsimpl-tick-factor=10000 TEST_HC=ghc-7.11.20150711
...
T2497.hs:18:1: warning: Defined but not used: ‘beq’
ghc: panic! (the 'impossible' happened)
  (GHC version 7.11.20150711 for x86_64-unknown-linux):
	Simplifier ticks exhausted
  When trying RuleFired rule 1
  To increase the limit, use -fsimpl-tick-factor=N (default 100)
  If you need to do this, let GHC HQ know, and what factor you needed
  To see detailed counts use -ddump-simpl-stats
  Total ticks: 40000
...

The test is very small:

module ShouldCompile() where

eq :: Eq a => a -> a -> Bool
eq = (==)

{-# RULES
    "rule 1" forall x y. x == y = y `eq` x
  #-}

The problem does not occur with ghc-7.10.1. Curiously the problem goes away when I change the module header to module ShouldCompile where.

Trac metadata

Trac field	Value
Version	7.11
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Compiler
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