re PR tree-optimization/21001 (VRP is weak when the tested variable in a COND_EXPR is used only in the COND_EXPR.)

gcc/
	PR tree-optimization/21001
	* tree-optimize.c (init_tree_optimization_passes): Move the
	first pass_forwprop immediately before pass_vrp.

testsuite/
	PR tree-optimization/21001
	* gcc.dg/tree-ssa/pr21001.c: New.

From-SVN: r98309