Hello, Here is updated patch for tree reassoc phase. Update includes coding style fixes, comments update, target hook arguments change. I also moved a part of code from rewrite_expr_tree into separate function to reuse it in rewrite_expr_tree_parallel for grouping operands with the same rank. Bootstrapped and checked on x86_64-linux. Ilya -- gcc/ 2011-07-26 Enkovich Ilya PR middle-end/44382 * target.def (reassociation_width): New hook. * doc/tm.texi.in (reassociation_width): Likewise. * doc/tm.texi (reassociation_width): Likewise. * doc/invoke.texi (tree-reassoc-width): New param documented. * hooks.h (hook_int_uint_mode_1): New default hook. * hooks.c (hook_int_uint_mode_1): Likewise. * config/i386/i386.h (ix86_tune_indices): Add X86_TUNE_REASSOC_INT_TO_PARALLEL and X86_TUNE_REASSOC_FP_TO_PARALLEL. (TARGET_REASSOC_INT_TO_PARALLEL): New. (TARGET_REASSOC_FP_TO_PARALLEL): Likewise. * config/i386/i386.c (initial_ix86_tune_features): Add X86_TUNE_REASSOC_INT_TO_PARALLEL and X86_TUNE_REASSOC_FP_TO_PARALLEL. (ix86_reassociation_width) implementation of new hook for i386 target. * params.def (PARAM_TREE_REASSOC_WIDTH): New param added. * tree-ssa-reassoc.c (get_required_cycles): New function. (get_reassociation_width): Likewise. (swap_ops_for_binary_stmt): Likewise. (rewrite_expr_tree_parallel): Likewise. (rewrite_expr_tree): Refactored. Part of code moved into swap_ops_for_binary_stmt. (reassociate_bb): Now checks reassociation width to be used and call rewrite_expr_tree_parallel instead of rewrite_expr_tree if needed. (pass_reassoc): TODO_remove_unused_locals flag added. gcc/testsuite/ 2011-07-26 Enkovich Ilya * gcc.dg/tree-ssa/pr38533.c (dg-options): Added option --param tree-reassoc-width=1. * gcc.dg/tree-ssa/reassoc-24.c: New test. * gcc.dg/tree-ssa/reassoc-25.c: Likewise.