Hi,

when compiling vector-algorithms on powerpc, I get

[ 7 of 10] Compiling Data.Vector.Algorithms.Tim ( src/Data/Vector/Algorithms/Tim.hs, dist-ghc/build/Data/Vector/Algorithms/Tim.o )
ghc: panic! (the 'impossible' happened)
  (GHC version 7.10.2 for powerpc-unknown-linux):
	PPC.Ppr: Shift by 32 bits is not allowed.

I do not get this error on other 32bit architectures.

The offending code seems to be

minrun :: Int -> Int
minrun n0 = (n0 `unsafeShiftR` extra) + if (lowMask .&. n0) > 0 then 1 else 0
 where
 -- smear the bits down from the most significant bit
 !n1 = n0 .|. unsafeShiftR n0 1
 !n2 = n1 .|. unsafeShiftR n1 2
 !n3 = n2 .|. unsafeShiftR n2 4
 !n4 = n3 .|. unsafeShiftR n3 8
 !n5 = n4 .|. unsafeShiftR n4 16
 !n6 = n5 .|. unsafeShiftR n5 32

The call to panic was introduced by Erik in the fix for #5900 (closed).

Is the code at fault, or the compiler?