diff options
Diffstat (limited to 'gcc/tree-ssa-alias.c')
| -rw-r--r-- | gcc/tree-ssa-alias.c | 123 |
1 files changed, 63 insertions, 60 deletions
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c index 64476ebe301..94ccd800929 100644 --- a/gcc/tree-ssa-alias.c +++ b/gcc/tree-ssa-alias.c @@ -175,13 +175,6 @@ bitmap call_clobbered_vars; variable). */ bitmap addressable_vars; -/* 'true' after aliases have been computed (see compute_may_aliases). This - is used by get_stmt_operands and its helpers to determine what to do - when scanning an operand for a variable that may be aliased. If - may-alias information is still not available, the statement is marked as - having volatile operands. */ -bool aliases_computed_p; - /* When the program has too many call-clobbered variables and call-sites, this variable is used to represent the clobbering effects of function calls. In these cases, all the call clobbered variables in the program @@ -350,9 +343,6 @@ compute_may_aliases (void) /* Deallocate memory used by aliasing data structures. */ delete_alias_info (ai); - - /* Indicate that may-alias information is now available. */ - aliases_computed_p = true; } struct tree_opt_pass pass_may_alias = @@ -365,7 +355,7 @@ struct tree_opt_pass pass_may_alias = 0, /* static_pass_number */ TV_TREE_MAY_ALIAS, /* tv_id */ PROP_cfg | PROP_ssa | PROP_pta, /* properties_required */ - 0, /* properties_provided */ + PROP_alias, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_dump_func | TODO_rename_vars @@ -379,6 +369,7 @@ static struct alias_info * init_alias_info (void) { struct alias_info *ai; + static bool aliases_computed_p = false; ai = xcalloc (1, sizeof (struct alias_info)); ai->ssa_names_visited = BITMAP_XMALLOC (); @@ -417,14 +408,8 @@ init_alias_info (void) for (i = 0; i < num_referenced_vars; i++) { var_ann_t ann = var_ann (referenced_var (i)); - ann->is_alias_tag = 0; - if (ann->type_mem_tag) - { - var_ann_t tag_ann = var_ann (ann->type_mem_tag); - tag_ann->may_aliases = NULL; - bitmap_set_bit (vars_to_rename, tag_ann->uid); - } + ann->may_aliases = NULL; } /* Clear flow-sensitive points-to information from each SSA name. */ @@ -450,12 +435,13 @@ init_alias_info (void) pi->is_dereferenced = 0; if (pi->pt_vars) bitmap_clear (pi->pt_vars); - if (pi->name_mem_tag) - var_ann (pi->name_mem_tag)->may_aliases = NULL; } } } + /* Next time, we will need to reset alias information. */ + aliases_computed_p = true; + return ai; } @@ -1375,47 +1361,64 @@ setup_pointers_and_addressables (struct alias_info *ai) /* Add pointer variables that have been dereferenced to the POINTERS array and create a type memory tag for them. */ - if (POINTER_TYPE_P (TREE_TYPE (var)) - && (bitmap_bit_p (ai->dereferenced_ptrs_store, v_ann->uid) - || bitmap_bit_p (ai->dereferenced_ptrs_load, v_ann->uid))) + if (POINTER_TYPE_P (TREE_TYPE (var))) { - tree tag; - var_ann_t t_ann; - - /* If pointer VAR still doesn't have a memory tag associated - with it, create it now or re-use an existing one. */ - tag = get_tmt_for (var, ai); - t_ann = var_ann (tag); - - /* The type tag will need to be renamed into SSA afterwards. - Note that we cannot do this inside get_tmt_for because - aliasing may run multiple times and we only create type - tags the first time. */ - bitmap_set_bit (vars_to_rename, t_ann->uid); - - /* Associate the tag with pointer VAR. */ - v_ann->type_mem_tag = tag; - - /* If pointer VAR has been used in a store operation, then its - memory tag must be marked as written-to. */ - if (bitmap_bit_p (ai->dereferenced_ptrs_store, v_ann->uid)) - bitmap_set_bit (ai->written_vars, t_ann->uid); - - /* If pointer VAR is a global variable or a PARM_DECL, then its - memory tag should be considered a global variable. */ - if (TREE_CODE (var) == PARM_DECL || needs_to_live_in_memory (var)) - mark_call_clobbered (tag); - - /* All the dereferences of pointer VAR count as references of - TAG. Since TAG can be associated with several pointers, add - the dereferences of VAR to the TAG. We may need to grow - AI->NUM_REFERENCES because we have been adding name and - type tags. */ - if (t_ann->uid >= VARRAY_SIZE (ai->num_references)) - VARRAY_GROW (ai->num_references, t_ann->uid + 10); - - VARRAY_UINT (ai->num_references, t_ann->uid) - += VARRAY_UINT (ai->num_references, v_ann->uid); + if ((bitmap_bit_p (ai->dereferenced_ptrs_store, v_ann->uid) + || bitmap_bit_p (ai->dereferenced_ptrs_load, v_ann->uid))) + { + tree tag; + var_ann_t t_ann; + + /* If pointer VAR still doesn't have a memory tag + associated with it, create it now or re-use an + existing one. */ + tag = get_tmt_for (var, ai); + t_ann = var_ann (tag); + + /* The type tag will need to be renamed into SSA + afterwards. Note that we cannot do this inside + get_tmt_for because aliasing may run multiple times + and we only create type tags the first time. */ + bitmap_set_bit (vars_to_rename, t_ann->uid); + + /* Associate the tag with pointer VAR. */ + v_ann->type_mem_tag = tag; + + /* If pointer VAR has been used in a store operation, + then its memory tag must be marked as written-to. */ + if (bitmap_bit_p (ai->dereferenced_ptrs_store, v_ann->uid)) + bitmap_set_bit (ai->written_vars, t_ann->uid); + + /* If pointer VAR is a global variable or a PARM_DECL, + then its memory tag should be considered a global + variable. */ + if (TREE_CODE (var) == PARM_DECL || needs_to_live_in_memory (var)) + mark_call_clobbered (tag); + + /* All the dereferences of pointer VAR count as + references of TAG. Since TAG can be associated with + several pointers, add the dereferences of VAR to the + TAG. We may need to grow AI->NUM_REFERENCES because + we have been adding name and type tags. */ + if (t_ann->uid >= VARRAY_SIZE (ai->num_references)) + VARRAY_GROW (ai->num_references, t_ann->uid + 10); + + VARRAY_UINT (ai->num_references, t_ann->uid) + += VARRAY_UINT (ai->num_references, v_ann->uid); + } + else + { + /* The pointer has not been dereferenced. If it had a + type memory tag, remove it and mark the old tag for + renaming to remove it out of the IL. */ + var_ann_t ann = var_ann (var); + tree tag = ann->type_mem_tag; + if (tag) + { + bitmap_set_bit (vars_to_rename, var_ann (tag)->uid); + ann->type_mem_tag = NULL_TREE; + } + } } } |