void gsi_move_to_bb_end (gimple_stmt_iterator *from, basic_block bb) { gimple_stmt_iterator last = gsi_last_bb (bb); gcc_checking_assert (gsi_bb (last) == bb); /* Have to check gsi_end_p because it could be an empty block. */ if (!gsi_end_p (last) && is_ctrl_stmt (gsi_stmt (last))) gsi_move_before (from, &last); else gsi_move_after (from, &last); }
static bool minmax_replacement (basic_block cond_bb, basic_block middle_bb, edge e0, edge e1, gimple phi, tree arg0, tree arg1) { tree result, type; gimple cond, new_stmt; edge true_edge, false_edge; enum tree_code cmp, minmax, ass_code; tree smaller, larger, arg_true, arg_false; gimple_stmt_iterator gsi, gsi_from; type = TREE_TYPE (PHI_RESULT (phi)); /* The optimization may be unsafe due to NaNs. */ if (HONOR_NANS (TYPE_MODE (type))) return false; cond = last_stmt (cond_bb); cmp = gimple_cond_code (cond); result = PHI_RESULT (phi); /* This transformation is only valid for order comparisons. Record which operand is smaller/larger if the result of the comparison is true. */ if (cmp == LT_EXPR || cmp == LE_EXPR) { smaller = gimple_cond_lhs (cond); larger = gimple_cond_rhs (cond); } else if (cmp == GT_EXPR || cmp == GE_EXPR) { smaller = gimple_cond_rhs (cond); larger = gimple_cond_lhs (cond); } else return false; /* We need to know which is the true edge and which is the false edge so that we know if have abs or negative abs. */ extract_true_false_edges_from_block (cond_bb, &true_edge, &false_edge); /* Forward the edges over the middle basic block. */ if (true_edge->dest == middle_bb) true_edge = EDGE_SUCC (true_edge->dest, 0); if (false_edge->dest == middle_bb) false_edge = EDGE_SUCC (false_edge->dest, 0); if (true_edge == e0) { gcc_assert (false_edge == e1); arg_true = arg0; arg_false = arg1; } else { gcc_assert (false_edge == e0); gcc_assert (true_edge == e1); arg_true = arg1; arg_false = arg0; } if (empty_block_p (middle_bb)) { if (operand_equal_for_phi_arg_p (arg_true, smaller) && operand_equal_for_phi_arg_p (arg_false, larger)) { /* Case if (smaller < larger) rslt = smaller; else rslt = larger; */ minmax = MIN_EXPR; } else if (operand_equal_for_phi_arg_p (arg_false, smaller) && operand_equal_for_phi_arg_p (arg_true, larger)) minmax = MAX_EXPR; else return false; } else { /* Recognize the following case, assuming d <= u: if (a <= u) b = MAX (a, d); x = PHI <b, u> This is equivalent to b = MAX (a, d); x = MIN (b, u); */ gimple assign = last_and_only_stmt (middle_bb); tree lhs, op0, op1, bound; if (!assign || gimple_code (assign) != GIMPLE_ASSIGN) return false; lhs = gimple_assign_lhs (assign); ass_code = gimple_assign_rhs_code (assign); if (ass_code != MAX_EXPR && ass_code != MIN_EXPR) return false; op0 = gimple_assign_rhs1 (assign); op1 = gimple_assign_rhs2 (assign); if (true_edge->src == middle_bb) { /* We got here if the condition is true, i.e., SMALLER < LARGER. */ if (!operand_equal_for_phi_arg_p (lhs, arg_true)) return false; if (operand_equal_for_phi_arg_p (arg_false, larger)) { /* Case if (smaller < larger) { r' = MAX_EXPR (smaller, bound) } r = PHI <r', larger> --> to be turned to MIN_EXPR. */ if (ass_code != MAX_EXPR) return false; minmax = MIN_EXPR; if (operand_equal_for_phi_arg_p (op0, smaller)) bound = op1; else if (operand_equal_for_phi_arg_p (op1, smaller)) bound = op0; else return false; /* We need BOUND <= LARGER. */ if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, bound, larger))) return false; } else if (operand_equal_for_phi_arg_p (arg_false, smaller)) { /* Case if (smaller < larger) { r' = MIN_EXPR (larger, bound) } r = PHI <r', smaller> --> to be turned to MAX_EXPR. */ if (ass_code != MIN_EXPR) return false; minmax = MAX_EXPR; if (operand_equal_for_phi_arg_p (op0, larger)) bound = op1; else if (operand_equal_for_phi_arg_p (op1, larger)) bound = op0; else return false; /* We need BOUND >= SMALLER. */ if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, bound, smaller))) return false; } else return false; } else { /* We got here if the condition is false, i.e., SMALLER > LARGER. */ if (!operand_equal_for_phi_arg_p (lhs, arg_false)) return false; if (operand_equal_for_phi_arg_p (arg_true, larger)) { /* Case if (smaller > larger) { r' = MIN_EXPR (smaller, bound) } r = PHI <r', larger> --> to be turned to MAX_EXPR. */ if (ass_code != MIN_EXPR) return false; minmax = MAX_EXPR; if (operand_equal_for_phi_arg_p (op0, smaller)) bound = op1; else if (operand_equal_for_phi_arg_p (op1, smaller)) bound = op0; else return false; /* We need BOUND >= LARGER. */ if (!integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node, bound, larger))) return false; } else if (operand_equal_for_phi_arg_p (arg_true, smaller)) { /* Case if (smaller > larger) { r' = MAX_EXPR (larger, bound) } r = PHI <r', smaller> --> to be turned to MIN_EXPR. */ if (ass_code != MAX_EXPR) return false; minmax = MIN_EXPR; if (operand_equal_for_phi_arg_p (op0, larger)) bound = op1; else if (operand_equal_for_phi_arg_p (op1, larger)) bound = op0; else return false; /* We need BOUND <= SMALLER. */ if (!integer_nonzerop (fold_build2 (LE_EXPR, boolean_type_node, bound, smaller))) return false; } else return false; } /* Move the statement from the middle block. */ gsi = gsi_last_bb (cond_bb); gsi_from = gsi_last_bb (middle_bb); gsi_move_before (&gsi_from, &gsi); } /* Emit the statement to compute min/max. */ result = duplicate_ssa_name (PHI_RESULT (phi), NULL); new_stmt = gimple_build_assign_with_ops (minmax, result, arg0, arg1); gsi = gsi_last_bb (cond_bb); gsi_insert_before (&gsi, new_stmt, GSI_NEW_STMT); replace_phi_edge_with_variable (cond_bb, e1, phi, result); return true; }