2011-10-23 Tom de Vries <tom@codesourcery.com>
PR tree-optimization/50763
* tree-ssa-tail-merge.c (same_succ_flush_bb): New function, factored out
of ...
(same_succ_flush_bbs): Use same_succ_flush_bb.
(purge_bbs): Remove argument. Remove calls to same_succ_flush_bbs,
release_last_vdef and delete_basic_block.
(unlink_virtual_phi): New function.
(update_vuses): Add and use vuse1_phi_args argument. Set var to
SSA_NAME_VAR of vuse1 or vuse2, and use var. Handle case that def_stmt2
is NULL. Use phi result as phi arg in case vuse1 or vuse2 is NULL_TREE.
Replace uses of vuse1 if vuse2 is NULL_TREE. Fix code to limit
replacement of uses. Propagate phi argument for phis with a single
argument.
(replace_block_by): Update vops if phi_vuse1 or phi_vuse2 is NULL_TREE.
Set vuse1_phi_args if vuse1 is a phi defined in bb1. Add vuse1_phi_args
as argument to call to update_vuses. Call release_last_vdef,
same_succ_flush_bb, delete_basic_block. Update CDI_DOMINATORS info.
(tail_merge_optimize): Remove argument in call to purge_bbs. Remove
call to free_dominance_info. Only call calculate_dominance_info once.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@180341
138bc75d-0d04-0410-961f-
82ee72b054a4