re PR tree-optimization/46985 (ICE: SIGSEGV in is_gimple_min_invariant (gimple.c:2742) with -fno-tree-ccp -fno-tree-dominator-opts -fno-tree-fre)

	PR tree-optimization/46985
	* tree-scalar-evolution.c (instantiate_scev_r): If chrec is NULL,
	return it immediately.

	* gfortran.dg/pr46985.f90: New test.

From-SVN: r168027