HEAD build fails when building way=p with WAY_p_OPTS='-prof -caf-all -auto-all'

Specifically, the failure happens while compiling libraries/base/Data/Complex.hs:

compiler output:

/Users/pgavin/local/ghc-6.9/src/ghc-6.9/compiler/stage1/ghc-inplace -package-name base-3.0 -hide-all-packages -split-objs -i -idist/build -i. -idist/build/autogen -Idist/build -Iinclude -#include "HsBase.h" -odir dist/build -hidir dist/build -stubdir dist/build -package ghc-prim-0.1 -package integer-0.1 -package rts-1.0 -O -package-name base -XMagicHash -XExistentialQuantification -XRank2Types -XScopedTypeVariables -XUnboxedTuples -XForeignFunctionInterface -XUnliftedFFITypes -XDeriveDataTypeable -XGeneralizedNewtypeDeriving -XFlexibleInstances -XPatternSignatures -XStandaloneDeriving -XPatternGuards -XCPP -idist/build  -prof -caf-all -auto-all -hisuf p_hi -hcsuf p_hc -osuf p_o -H32m -O -H32m -O2 -O2 -Rghc-timing -XGenerics -O2 -Wall -fno-warn-deprecated-flags -w  -c Data/Complex.hs -o dist/build/Data/Complex.p_o  -ohi dist/build/Data/Complex.p_hi

/var/folders/o2/o2fca1ekG9SKEu61XaHsjE+++TI/-Tmp-/ghc51695_0/ghc51695_0.split__108.s:1256:0:
    FATAL:Symbol _base_DataziComplex_zeze_CAF_cc_ccs already defined.

Compilation succeeds if the SPECIALIZE pragmas are removed from the instance declarations for Num, Fractional, and Floating.