[09/46] Add vec_info::lookup_single_use
This patch adds a helper function for seeing whether there is a single
user of an SSA name, and whether that user has a stmt_vec_info.
2018-07-31 Richard Sandiford <richard.sandiford@arm.com>
gcc/
* tree-vectorizer.h (vec_info::lookup_single_use): Declare.
* tree-vectorizer.c (vec_info::lookup_single_use): New function.
* tree-vect-loop.c (vectorizable_reduction): Use it instead of
a single_imm_use-based sequence.
* tree-vect-stmts.c (supportable_widening_operation): Likewise.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@263124 138bc75d-0d04-0410-961f-82ee72b054a4