extend DECL_GIMPLE_REG_P to all types

This extends DECL_GIMPLE_REG_P to all types so we can clear
TREE_ADDRESSABLE even for integers with partial defs, not just
complex and vector variables.  To make that transition easier
the patch inverts DECL_GIMPLE_REG_P to DECL_NOT_GIMPLE_REG_P
since that makes the default the current state for all other
types besides complex and vectors.

For the testcase in PR94703 we're able to expand the partial
def'ed local integer to a register then, producing a single
movl rather than going through the stack.

On i?86 this execute FAILs gcc.dg/torture/pr71522.c because
we now expand a round-trip through a long double automatic var
to a register fld/fst which normalizes the value.  For that
during RTL expansion we're looking for problematic punnings
of decls and avoid pseudos for those - I chose integer or
BLKmode accesses on decls with modes where precision doesn't
match bitsize which covers the XFmode case.

2020-05-07  Richard Biener  <rguenther@suse.de>

	PR middle-end/94703
	* tree-core.h (tree_decl_common::gimple_reg_flag): Rename ...
	(tree_decl_common::not_gimple_reg_flag): ... to this.
	* tree.h (DECL_GIMPLE_REG_P): Rename ...
	(DECL_NOT_GIMPLE_REG_P): ... to this.
	* gimple-expr.c (copy_var_decl): Copy DECL_NOT_GIMPLE_REG_P.
	(create_tmp_reg): Simplify.
	(create_tmp_reg_fn): Likewise.
	(is_gimple_reg): Check DECL_NOT_GIMPLE_REG_P for all regs.
	* gimplify.c (create_tmp_from_val): Simplify.
	(gimplify_bind_expr): Likewise.
	(gimplify_compound_literal_expr): Likewise.
	(gimplify_function_tree): Likewise.
	(prepare_gimple_addressable): Set DECL_NOT_GIMPLE_REG_P.
	* asan.c (create_odr_indicator): Do not clear DECL_GIMPLE_REG_P.
	(asan_add_global): Copy it.
	* cgraphunit.c (cgraph_node::expand_thunk): Force args
	to be GIMPLE regs.
	* function.c (gimplify_parameters): Copy
	DECL_NOT_GIMPLE_REG_P.
	* ipa-param-manipulation.c
	(ipa_param_body_adjustments::common_initialization): Simplify.
	(ipa_param_body_adjustments::reset_debug_stmts): Copy
	DECL_NOT_GIMPLE_REG_P.
	* omp-low.c (lower_omp_for_scan): Do not set DECL_GIMPLE_REG_P.
	* sanopt.c (sanitize_rewrite_addressable_params): Likewise.
	* tree-cfg.c (make_blocks_1): Simplify.
	(verify_address): Do not verify DECL_GIMPLE_REG_P setting.
	* tree-eh.c (lower_eh_constructs_2): Simplify.
	* tree-inline.c (declare_return_variable): Adjust and
	generalize.
	(copy_decl_to_var): Copy DECL_NOT_GIMPLE_REG_P.
	(copy_result_decl_to_var): Likewise.
	* tree-into-ssa.c (pass_build_ssa::execute): Adjust comment.
	* tree-nested.c (create_tmp_var_for): Simplify.
	* tree-parloops.c (separate_decls_in_region_name): Copy
	DECL_NOT_GIMPLE_REG_P.
	* tree-sra.c (create_access_replacement): Adjust and
	generalize partial def support.
	* tree-ssa-forwprop.c (pass_forwprop::execute): Set
	DECL_NOT_GIMPLE_REG_P on decls we introduce partial defs on.
	* tree-ssa.c (maybe_optimize_var): Handle clearing of
	TREE_ADDRESSABLE and setting/clearing DECL_NOT_GIMPLE_REG_P
	independently.
	* lto-streamer-out.c (hash_tree): Hash DECL_NOT_GIMPLE_REG_P.
	* tree-streamer-out.c (pack_ts_decl_common_value_fields): Stream
	DECL_NOT_GIMPLE_REG_P.
	* tree-streamer-in.c (unpack_ts_decl_common_value_fields): Likewise.
	* cfgexpand.c (avoid_type_punning_on_regs): New.
	(discover_nonconstant_array_refs): Call
	avoid_type_punning_on_regs to avoid unsupported mode punning.

	lto/
	* lto-common.c (compare_tree_sccs_1): Compare
	DECL_NOT_GIMPLE_REG_P.

	c/
	* gimple-parser.c (c_parser_parse_ssa_name): Do not set
	DECL_GIMPLE_REG_P.

	cp/
	* optimize.c (update_cloned_parm): Copy DECL_NOT_GIMPLE_REG_P.

	* gcc.dg/tree-ssa/pr94703.c: New testcase.