[12/46] Make vect_finish_stmt_generation return a stmt_vec_info

[12/46] Make vect_finish_stmt_generation return a stmt_vec_info

This patch makes vect_finish_replace_stmt and vect_finish_stmt_generation
return the stmt_vec_info for the vectorised statement, so that the caller
doesn't need a separate vinfo_for_stmt to get at it.

This involved changing the structure of the statement-generating loops
so that they use narrow scopes for the vectorised gimple statements
and use the existing (wider) scopes for the associated stmt_vec_infos.
This helps with gimple stmt->stmt_vec_info changes further down the line.

The way we do this generation is another area ripe for clean-up,
but that's too much of a rabbit-hole for this series.

2018-07-31  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* tree-vectorizer.h (vect_finish_replace_stmt): Return a stmt_vec_info
	(vect_finish_stmt_generation): Likewise.
	* tree-vect-stmts.c (vect_finish_stmt_generation_1): Likewise.
	(vect_finish_replace_stmt, vect_finish_stmt_generation): Likewise.
	(vect_build_gather_load_calls): Use the return value of the above
	functions instead of a separate call to vinfo_for_stmt.  Use narrow
	scopes for the input gimple stmt and wider scopes for the associated
	stmt_vec_info.  Use vec_info::lookup_def when setting these
	stmt_vec_infos from an SSA_NAME definition.
	(vectorizable_bswap, vectorizable_call, vectorizable_simd_clone_call)
	(vect_create_vectorized_demotion_stmts, vectorizable_conversion)
	(vectorizable_assignment, vectorizable_shift, vectorizable_operation)
	(vectorizable_store, vectorizable_load, vectorizable_condition)
	(vectorizable_comparison): Likewise.
	* tree-vect-loop.c (vectorize_fold_left_reduction): Likewise.
	(vectorizable_reduction): Likewise.

From-SVN: r263127