(Optimized prime generation) ghc: panic! (the 'impossible' happened)

I try to compile the example from https://wiki.haskell.org/Prime_numbers#Using_ST_Array

{-# OPTIONS_GHC -O2 #-}

import Control.Monad
import Control.Monad.ST
import Data.Array.ST
import Data.Array.Unboxed
 
sieveUA :: Int -> UArray Int Bool
sieveUA top = runSTUArray $ do
    let m = (top-1) `div` 2
        r = floor . sqrt $ fromIntegral top + 1
    sieve <- newArray (1,m) True      -- :: ST s (STUArray s Int Bool)
    forM_ [1..r `div` 2] $ \i -> do
      isPrime <- readArray sieve i
      when isPrime $ do               -- ((2*i+1)^2-1)`div`2 == 2*i*(i+1)
        forM_ [2*i*(i+1), 2*i*(i+2)+1..m] $ \j -> do
          writeArray sieve j False
    return sieve

I get the following error:

[1 of 1] Compiling Main             ( p111.hs, interpreted )
ghc: panic! (the 'impossible' happened)
  (GHC version 7.10.2 for x86_64-unknown-linux):
	floatExpr tick break<29>()

Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

The error does not happen if I remove the OPTIONS_GHC -O2 directive. I use ArchLinux and the GHC compiled package from it's standard repositories.

Trac metadata

Trac field	Value
Version	7.10.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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