re PR tree-optimization/47060 (ICE: SIGSEGV in reduction_phi (tree-parloops.c:212) with -O -ffast-math -ftree-parallelize-loops=2 -fno-tree-dce)

	PR tree-optimization/47060
	* tree-parloops.c (reduction_phi): Return NULL if PHI is NULL.

	* gcc.dg/autopar/pr47060.c: New test.

From-SVN: r168336