backport: re PR tree-optimization/91137 (Wrong code with -O3)

backport: re PR tree-optimization/91137 (Wrong code with -O3)

	Backport from mainline
	2019-07-18  Bin Cheng  <bin.linux@linux.alibaba.com>

	PR tree-optimization/91137
	* tree-ssa-loop-ivopts.c (struct ivopts_data): New field.
	(tree_ssa_iv_optimize_init, alloc_iv, tree_ssa_iv_optimize_finalize):
	Init, use and fini the above new field.
	(determine_base_object_1): New function.
	(determine_base_object): Reimplement using walk_tree.

	2019-07-18  Bin Cheng  <bin.linux@linux.alibaba.com>

	PR tree-optimization/91137
	* gcc.c-torture/execute/pr91137.c: New test.

From-SVN: r275304