....
- # A new variable is created for each reduction:
- "reduction_initial" is the initial value given by the user.
- It is kept and will be used after the parallel computing is done. #
+ # Storing the the initial value given by the user. #
- reduction_initial.24_46 = 1;
-
- # Storing the neutral value of the
- particular reduction's operation, e.g. 0 for PLUS_EXPR,
- 1 for MULT_EXPR, etc. into the reduction field.
- This is done in create_stores_for_reduction. #
+ .paral_data_store.32.sum.27 = 1;
- .paral_data_store.32.sum.27 = 0;
-
#pragma omp parallel num_threads(4)
#pragma omp for schedule(static)
- # sum.27_29 = PHI <sum.27_11, 0> # The neutral element replaces
- the user's inital value. #
+
+ # The neutral element corresponding to the particular
+ reduction's operation, e.g. 0 for PLUS_EXPR,
+ 1 for MULT_EXPR, etc. replaces the user's initial value. #
+
+ # sum.27_29 = PHI <sum.27_11, 0>
+
sum.27_11 = D.1827_8 + sum.27_29;
+
OMP_CONTINUE
# Adding this reduction phi is done at create_phi_for_local_result() #
# collecting the result after the join of the threads is done at
create_loads_for_reductions().
- a new variable "reduction_final" is created. It calculates the final
- value from the initial value and the value computed by the threads #
+ The value computed by the threads is loaded from the
+ shared struct. #
+
.paral_data_load.33_52 = &.paral_data_store.32;
- reduction_final.34_53 = .paral_data_load.33_52->sum.27;
- sum_37 = reduction_initial.24_46 + reduction_final.34_53;
+ sum_37 = .paral_data_load.33_52->sum.27;
sum_43 = D.1795_41 + sum_37;
exit bb:
enum tree_code reduction_code; /* code for the reduction operation. */
tree keep_res; /* The PHI_RESULT of this phi is the resulting value
of the reduction variable when existing the loop. */
- tree initial_value; /* An ssa name representing a new variable holding
- the initial value of the reduction var before entering the loop. */
+ tree initial_value; /* The initial value of the reduction var before entering the loop. */
tree field; /* the name of the field in the parloop data structure intended for reduction. */
tree init; /* reduction initialization value. */
tree new_phi; /* (helper field) Newly created phi node whose result
static int
initialize_reductions (void **slot, void *data)
{
- tree stmt;
tree init, c;
- tree name1;
tree bvar, type, arg;
edge e;
e = loop_preheader_edge (loop);
arg = PHI_ARG_DEF_FROM_EDGE (reduc->reduc_phi, e);
/* Create new variable to hold the initial value. */
- type = TREE_TYPE (bvar);
- bvar = create_tmp_var (type, "reduction_initial");
- add_referenced_var (bvar);
- stmt = build_gimple_modify_stmt (bvar, arg);
- name1 = make_ssa_name (bvar, stmt);
- GIMPLE_STMT_OPERAND (stmt, 0) = name1;
- SSA_NAME_DEF_STMT (name1) = stmt;
-
- bsi_insert_on_edge_immediate (e, stmt);
SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE
(reduc->reduc_phi, loop_preheader_edge (loop)), init);
- reduc->initial_value = name1;
+ reduc->initial_value = arg;
return 1;
}
htab_traverse (reduction_list, create_call_for_reduction_1, ld_st_data);
}
-/* Callback for htab_traverse. Create a new variable that loads the
- final reduction value at the
- join point of all threads, adds the initial value the reduction
- variable had before the parallel computation started, and
- inserts it in the right place. */
+/* Callback for htab_traverse. Loads the final reduction value at the
+ join point of all threads, and inserts it in the right place. */
static int
create_loads_for_reductions (void **slot, void *data)
tree type = TREE_TYPE (GIMPLE_STMT_OPERAND (red->reduc_stmt, 0));
tree struct_type = TREE_TYPE (TREE_TYPE (clsn_data->load));
tree load_struct;
- tree bvar, name;
+ tree name;
tree x;
bsi = bsi_after_labels (clsn_data->load_bb);
load_struct = fold_build1 (INDIRECT_REF, struct_type, clsn_data->load);
load_struct = build3 (COMPONENT_REF, type, load_struct, red->field,
NULL_TREE);
- bvar = create_tmp_var (type, "reduction_final");
- add_referenced_var (bvar);
-
- /* Apply operation between the new variable which is the result
- of computation all threads, and the initial value which is kept
- at reduction->inital_value. */
- stmt = build_gimple_modify_stmt (bvar, load_struct);
- name = make_ssa_name (bvar, stmt);
- GIMPLE_STMT_OPERAND (stmt, 0) = name;
- SSA_NAME_DEF_STMT (name) = stmt;
- bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
- x =
- fold_build2 (red->reduction_code, TREE_TYPE (load_struct),
- name, red->initial_value);
+ x = load_struct;
name = PHI_RESULT (red->keep_res);
stmt = build_gimple_modify_stmt (name, x);
GIMPLE_STMT_OPERAND (stmt, 0) = name;
build_gimple_modify_stmt (build3
(COMPONENT_REF, type, clsn_data->store,
red->field, NULL_TREE),
- red->init );
+ red->initial_value);
mark_virtual_ops_for_renaming (stmt);
bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
htab_traverse (name_copies, create_loads_and_stores_for_name,
ld_st_data);
- /* Load the calculation from memory into a new
- reduction variable (after the join of the threads). */
+ /* Load the calculation from memory (after the join of the threads). */
+
if (htab_elements (reduction_list) > 0)
{
htab_traverse (reduction_list, create_stores_for_reduction,
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