re PR c++/70906 (ice in add_expr, at tree.c:7925)

re PR c++/70906 (ice in add_expr, at tree.c:7925)

	PR c++/70906
	PR c++/70933
	* tree-core.h (enum operand_equal_flag): Add OEP_HASH_CHECK.
	* tree.c (inchash::add_expr): If !IS_EXPR_CODE_CLASS (tclass),
	assert flags & OEP_HASH_CHECK, instead of asserting it
	never happens.  Handle TARGET_EXPR.
	* fold-const.c (operand_equal_p): For hash verification,
	or in OEP_HASH_CHECK into flags.

	* g++.dg/opt/pr70906.C: New test.
	* g++.dg/opt/pr70933.C: New test.

From-SVN: r235902