PR middle-end/30391
	* tree.c (expr_align): Handle MODIFY_EXPR.  GIMPLE_MODIFY_STMT
	should be unreachable.
	(build2_stat): Allow construction of MODIFY_EXPR at any time.
	For the time being redirect GIMPLE_MODIFY_STMT to the new
	(renamed) build_gimple_modify_stmt_stat.
	(build2_gimple_stat): Rename to...
	(build_gimple_modify_stmt_stat): Now longer take a CODE argument.
	Always build a GIMPLE_MODIFY_STMT node.
	* tree.h (build2_gimple, build2_gimple_stat): Delete.
	(build_gimple_modify_stmt, build_gimple_modify_stmt_stat): New
	declarations.

	* tree-cfg.c (factor_computed_gotos, tree_merge_blocks,
	gimplify_val): Use build_gimple_modify_stmt instead of build2_gimple.
	* tree-complex.c (set_component_ssa_name, expand_complex_move,
	expand_complex_div_wide): Likewise.
	* tree-ssa-dom.c (record_equivalences_from_stmt): Likewise.
	* tree-ssa-loop-im.c (schedule_sm): Likewise.
	* tree-ssa-loop-ivopts.c (rewrite_use_nonlinear_expr): Likewise.
	* tree-ssa-loop-manip.c (create_iv): Likewise.
	* tree-ssa-phiopt.c (conditional_replacement, minmax_replacement,
	abs_replacement): Likewise.
	* tree-ssa-pre.c (create_expression_by_pieces, poolify_modify_stmt,
	realify_fake_stores): Likewise.

	* builtins.c (std_expand_builtin_va_start): Build a MODIFY_EXPR
	node rather than a GIMPLE_MODIFY_STMT node.
	(std_gimpify_va_arg_expr, expand_builtin_va_copy,
	fold_builtin_memset, fold_builtin_memory_op, do_mpfr_sincos):
	Likewise.
	(integer_valued_real_p): Handle MODIFY_EXPR, not GIMPLE_MODIFY_STMT.
	* expr.c (expand_expr_real_1): Handle both MODIFY_EXPR and
	GIMPLE_MODIFY_STMT.

	* gfortran.dg/pr30391-1.f90: New test case.

From-SVN: r122030