SRA: Total scalarization after access propagation [PR92706]

SRA: Total scalarization after access propagation [PR92706]

2020-01-29  Martin Jambor  <mjambor@suse.cz>

	PR tree-optimization/92706
	* tree-sra.c (struct access): Adjust comment of
	grp_total_scalarization.
	(find_access_in_subtree): Look for single children spanning an entire
	access.
	(scalarizable_type_p): Allow register accesses, adjust callers.
	(completely_scalarize): Remove function.
	(scalarize_elem): Likewise.
	(create_total_scalarization_access): Likewise.
	(sort_and_splice_var_accesses): Do not track total scalarization
	flags.
	(analyze_access_subtree): New parameter totally, adjust to new meaning
	of grp_total_scalarization.
	(analyze_access_trees): Pass new parameter to analyze_access_subtree.
	(can_totally_scalarize_forest_p): New function.
	(create_total_scalarization_access): Likewise.
	(create_total_access_and_reshape): Likewise.
	(total_should_skip_creating_access): Likewise.
	(totally_scalarize_subtree): Likewise.
	(analyze_all_variable_accesses): Perform total scalarization after
	subaccess propagation using the new functions above.
	(initialize_constant_pool_replacements): Output initializers by
	traversing the access tree.

	testsuite/
	* gcc.dg/tree-ssa/pr92706-2.c: New test.
	* gcc.dg/guality/pr59776.c: Xfail tests for s2.g.