+/* Check 2 instructions and determine if they can be safely
+ executed in parallel. Return 1 if they can be. */
+
+static int
+parallel_ok (op1, insn1, op2, insn2, exec_type)
+ struct d10v_opcode *op1, *op2;
+ unsigned long insn1, insn2;
+ packing_type exec_type;
+{
+ int i, j, flags, mask, shift, regno;
+ unsigned long ins, mod[2], used[2];
+ struct d10v_opcode *op;
+
+ if ((op1->exec_type & SEQ) != 0 || (op2->exec_type & SEQ) != 0
+ || (op1->exec_type & PAR) == 0 || (op2->exec_type & PAR) == 0
+ || (op1->unit == BOTH) || (op2->unit == BOTH)
+ || (op1->unit == IU && op2->unit == IU)
+ || (op1->unit == MU && op2->unit == MU))
+ return 0;
+
+ /* If this is auto parallization, and either instruction is a branch,
+ don't parallel. */
+ if (exec_type == PACK_UNSPEC
+ && (op1->exec_type & ALONE || op2->exec_type & ALONE))
+ return 0;
+
+ /* The idea here is to create two sets of bitmasks (mod and used)
+ which indicate which registers are modified or used by each
+ instruction. The operation can only be done in parallel if
+ instruction 1 and instruction 2 modify different registers, and
+ the first instruction does not modify registers that the second
+ is using (The second instruction can modify registers that the
+ first is using as they are only written back after the first
+ instruction has completed). Accesses to control registers, PSW,
+ and memory are treated as accesses to a single register. So if
+ both instructions write memory or if the first instruction writes
+ memory and the second reads, then they cannot be done in
+ parallel. Likewise, if the first instruction mucks with the psw
+ and the second reads the PSW (which includes C, F0, and F1), then
+ they cannot operate safely in parallel. */
+
+ /* The bitmasks (mod and used) look like this (bit 31 = MSB). */
+ /* r0-r15 0-15 */
+ /* a0-a1 16-17 */
+ /* cr (not psw) 18 */
+ /* psw 19 */
+ /* mem 20 */
+
+ for (j = 0; j < 2; j++)
+ {
+ if (j == 0)
+ {
+ op = op1;
+ ins = insn1;
+ }
+ else
+ {
+ op = op2;
+ ins = insn2;
+ }
+ mod[j] = used[j] = 0;
+ if (op->exec_type & BRANCH_LINK)
+ mod[j] |= 1 << 13;