+ if (vect_print_dump_info (REPORT_DETAILS))
+ fprintf (vect_dump, "type of def: %d.",*dt);
+
+ switch (TREE_CODE (*def_stmt))
+ {
+ case PHI_NODE:
+ *def = PHI_RESULT (*def_stmt);
+ gcc_assert (*dt == vect_induction_def || *dt == vect_reduction_def
+ || *dt == vect_invariant_def);
+ break;
+
+ case MODIFY_EXPR:
+ *def = TREE_OPERAND (*def_stmt, 0);
+ gcc_assert (*dt == vect_loop_def || *dt == vect_invariant_def);
+ break;
+
+ default:
+ if (vect_print_dump_info (REPORT_DETAILS))
+ fprintf (vect_dump, "unsupported defining stmt: ");
+ return false;
+ }
+
+ if (*dt == vect_induction_def)
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ fprintf (vect_dump, "induction not supported.");
+ return false;
+ }
+
+ return true;
+}
+
+
+/* Function reduction_code_for_scalar_code
+
+ Input:
+ CODE - tree_code of a reduction operations.
+
+ Output:
+ REDUC_CODE - the corresponding tree-code to be used to reduce the
+ vector of partial results into a single scalar result (which
+ will also reside in a vector).
+
+ Return TRUE if a corresponding REDUC_CODE was found, FALSE otherwise. */
+
+bool
+reduction_code_for_scalar_code (enum tree_code code,
+ enum tree_code *reduc_code)
+{
+ switch (code)
+ {
+ case MAX_EXPR:
+ *reduc_code = REDUC_MAX_EXPR;
+ return true;
+
+ case MIN_EXPR:
+ *reduc_code = REDUC_MIN_EXPR;
+ return true;
+
+ case PLUS_EXPR:
+ *reduc_code = REDUC_PLUS_EXPR;
+ return true;
+
+ default:
+ return false;
+ }
+}
+
+
+/* Function vect_is_simple_reduction
+
+ Detect a cross-iteration def-use cucle that represents a simple
+ reduction computation. We look for the following pattern:
+
+ loop_header:
+ a1 = phi < a0, a2 >
+ a3 = ...
+ a2 = operation (a3, a1)
+
+ such that:
+ 1. operation is commutative and associative and it is safe to
+ change the order of the computation.
+ 2. no uses for a2 in the loop (a2 is used out of the loop)
+ 3. no uses of a1 in the loop besides the reduction operation.
+
+ Condition 1 is tested here.
+ Conditions 2,3 are tested in vect_mark_stmts_to_be_vectorized. */
+
+tree
+vect_is_simple_reduction (struct loop *loop, tree phi)
+{
+ edge latch_e = loop_latch_edge (loop);
+ tree loop_arg = PHI_ARG_DEF_FROM_EDGE (phi, latch_e);
+ tree def_stmt, def1, def2;
+ enum tree_code code;
+ int op_type;
+ tree operation, op1, op2;
+ tree type;
+
+ if (TREE_CODE (loop_arg) != SSA_NAME)
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "reduction: not ssa_name: ");
+ print_generic_expr (vect_dump, loop_arg, TDF_SLIM);
+ }
+ return NULL_TREE;
+ }
+
+ def_stmt = SSA_NAME_DEF_STMT (loop_arg);
+ if (!def_stmt)
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ fprintf (vect_dump, "reduction: no def_stmt.");
+ return NULL_TREE;
+ }
+
+ if (TREE_CODE (def_stmt) != MODIFY_EXPR)
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ print_generic_expr (vect_dump, def_stmt, TDF_SLIM);
+ }
+ return NULL_TREE;
+ }
+
+ operation = TREE_OPERAND (def_stmt, 1);
+ code = TREE_CODE (operation);
+ if (!commutative_tree_code (code) || !associative_tree_code (code))
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "reduction: not commutative/associative: ");
+ print_generic_expr (vect_dump, operation, TDF_SLIM);
+ }
+ return NULL_TREE;
+ }
+
+ op_type = TREE_CODE_LENGTH (code);
+ if (op_type != binary_op)
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "reduction: not binary operation: ");
+ print_generic_expr (vect_dump, operation, TDF_SLIM);
+ }
+ return NULL_TREE;
+ }
+
+ op1 = TREE_OPERAND (operation, 0);
+ op2 = TREE_OPERAND (operation, 1);
+ if (TREE_CODE (op1) != SSA_NAME || TREE_CODE (op2) != SSA_NAME)
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "reduction: uses not ssa_names: ");
+ print_generic_expr (vect_dump, operation, TDF_SLIM);
+ }
+ return NULL_TREE;
+ }
+
+ /* Check that it's ok to change the order of the computation. */
+ type = TREE_TYPE (operation);
+ if (TYPE_MAIN_VARIANT (type) != TYPE_MAIN_VARIANT (TREE_TYPE (op1))
+ || TYPE_MAIN_VARIANT (type) != TYPE_MAIN_VARIANT (TREE_TYPE (op2)))
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "reduction: multiple types: operation type: ");
+ print_generic_expr (vect_dump, type, TDF_SLIM);
+ fprintf (vect_dump, ", operands types: ");
+ print_generic_expr (vect_dump, TREE_TYPE (op1), TDF_SLIM);
+ fprintf (vect_dump, ",");
+ print_generic_expr (vect_dump, TREE_TYPE (op2), TDF_SLIM);
+ }
+ return NULL_TREE;
+ }
+
+ /* CHECKME: check for !flag_finite_math_only too? */
+ if (SCALAR_FLOAT_TYPE_P (type) && !flag_unsafe_math_optimizations)
+ {
+ /* Changing the order of operations changes the semantics. */
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "reduction: unsafe fp math optimization: ");
+ print_generic_expr (vect_dump, operation, TDF_SLIM);
+ }
+ return NULL_TREE;
+ }
+ else if (INTEGRAL_TYPE_P (type) && !TYPE_UNSIGNED (type) && flag_trapv)
+ {
+ /* Changing the order of operations changes the semantics. */
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "reduction: unsafe int math optimization: ");
+ print_generic_expr (vect_dump, operation, TDF_SLIM);
+ }
+ return NULL_TREE;
+ }
+
+ /* reduction is safe. we're dealing with one of the following:
+ 1) integer arithmetic and no trapv
+ 2) floating point arithmetic, and special flags permit this optimization.
+ */
+ def1 = SSA_NAME_DEF_STMT (op1);
+ def2 = SSA_NAME_DEF_STMT (op2);
+ if (!def1 || !def2)
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "reduction: no defs for operands: ");
+ print_generic_expr (vect_dump, operation, TDF_SLIM);
+ }
+ return NULL_TREE;
+ }
+
+ if (TREE_CODE (def1) == MODIFY_EXPR
+ && flow_bb_inside_loop_p (loop, bb_for_stmt (def1))
+ && def2 == phi)
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "detected reduction:");
+ print_generic_expr (vect_dump, operation, TDF_SLIM);
+ }
+ return def_stmt;
+ }
+ else if (TREE_CODE (def2) == MODIFY_EXPR
+ && flow_bb_inside_loop_p (loop, bb_for_stmt (def2))
+ && def1 == phi)
+ {
+ /* Swap operands (just for simplicity - so that the rest of the code
+ can assume that the reduction variable is always the last (second)
+ argument). */
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "detected reduction: need to swap operands:");
+ print_generic_expr (vect_dump, operation, TDF_SLIM);
+ }
+ swap_tree_operands (def_stmt, &TREE_OPERAND (operation, 0),
+ &TREE_OPERAND (operation, 1));
+ return def_stmt;
+ }
+ else
+ {
+ if (vect_print_dump_info (REPORT_DETAILS))
+ {
+ fprintf (vect_dump, "reduction: unknown pattern.");
+ print_generic_expr (vect_dump, operation, TDF_SLIM);
+ }
+ return NULL_TREE;
+ }
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