GHC 7.10 complie time regression

[Kazu Yamamoto (=?iso-2022-jp?B?GyRCOzNLXE9CSScbKEI=?=)]

Hi,

I found that the compile time of GHC 7.10 against specific packages
gets much longer than previous versions. Here is example:

	https://travis-ci.org/kazu-yamamoto/iproute/builds/77427248

On my local MacBook Air, I see the same phenomena:

	GHC 7.8:  cabal build   8.81s user 0.94s system 103% cpu  9.430 total
	GHC 7.10: cabal build  37.86s user 3.49s system  98% cpu 42.066 total

Is this known regression?

--Kazu