nofib fannkuch-redux runs perpetually with -fllvm

Running the nofib benchmarks with make -k EXTRA_HC_OPTS=-fllvm on a HEAD build of ghc configured with perf-llvm (3.4.2) results in fannkuch-redux running in an infinite loop. The benchmark runs in about 3.5s without the -fllvm

HC = /Users/xx/Projects/ghc/inplace/bin/ghc-stage2
HC_OPTS = -O2 -Rghc-timing -H32m -hisuf hi -fllvm -rtsopts -XBangPatterns -O2
RUNTEST_OPTS = -ghc-timing
==nofib== fannkuch-redux: time to compile Main follows...
/Users/jrp/Projects/ghc/inplace/bin/ghc-stage2 -O2 -Rghc-timing -H32m -hisuf hi -fllvm -rtsopts -XBangPatterns -O2 -c Main.hs -o Main.o
<<ghc: 358716248 bytes, 313 GCs, 10827462/27497216 avg/max bytes residency (6 samples), 57M in use, 0.00 INIT (0.00 elapsed), 0.20 MUT (0.53 elapsed), 0.21 GC (0.23 elapsed) :ghc>>
==nofib== fannkuch-redux: size of Main.o follows...
__TEXT	__DATA	__OBJC	others	dec	hex
10333	497	0	0	10830	2a4e
==nofib== fannkuch-redux: time to link fannkuch-redux follows...
<<ghc: 19914544 bytes, 16 GCs, 1005021/2239600 avg/max bytes residency (3 samples), 25M in use, 0.00 INIT (0.00 elapsed), 0.01 MUT (0.53 elapsed), 0.02 GC (0.02 elapsed) :ghc>>
==nofib== fannkuch-redux: size of fannkuch-redux follows...
__TEXT	__DATA	__OBJC	others	dec	hex
4075520	446464	0	4295945496	4300467480	10053ed18
==nofib== fannkuch-redux: time to run fannkuch-redux follows...
../../runstdtest/runstdtest ./fannkuch-redux  -o1 fannkuch-redux.stdout -o1 fannkuch-redux.stdout  -ghc-timing     11;   ../../runstdtest/runstdtest ./fannkuch-redux  -o1 fannkuch-redux.stdout -o1 fannkuch-redux.stdout  -ghc-timing     11;   ../../runstdtest/runstdtest ./fannkuch-redux  -o1 fannkuch-redux.stdout -o1 fannkuch-redux.stdout  -ghc-timing     11;   ../../runstdtest/runstdtest ./fannkuch-redux  -o1 fannkuch-redux.stdout -o1 fannkuch-redux.stdout  -ghc-timing     11;   ../../runstdtest/runstdtest ./fannkuch-redux  -o1 fannkuch-redux.stdout -o1 fannkuch-redux.stdout  -ghc-timing     11;