re PR tree-optimization/71503 (gcc ICE at -O3 on valid code on x86_64-linux-gnu in "gen_phi_arg_condition")

	PR tree-optimization/71503
	PR tree-optimization/71683
	* tree-if-conv.c (gen_phi_arg_condition): Record true predicate
	and break.

	gcc/testsuite
	PR tree-optimization/71503
	PR tree-optimization/71683
	* gcc.dg/tree-ssa/ifc-pr71503.c: New test.
	* gcc.dg/tree-ssa/ifc-pr71683.c: New test.

From-SVN: r238512