+
+/* Returns whether R1 and R2 are uniquely chained: the value of one
+ is used by the other, and that value is not used by any other
+ reload for this insn. This is used to partially undo the decision
+ made in find_reloads when in the case of multiple
+ RELOAD_FOR_OPERAND_ADDRESS reloads it converts all
+ RELOAD_FOR_OPADDR_ADDR reloads into RELOAD_FOR_OPERAND_ADDRESS
+ reloads. This code tries to avoid the conflict created by that
+ change. It might be cleaner to explicitly keep track of which
+ RELOAD_FOR_OPADDR_ADDR reload is associated with which
+ RELOAD_FOR_OPERAND_ADDRESS reload, rather than to try to detect
+ this after the fact. */
+static bool
+reloads_unique_chain_p (int r1, int r2)
+{
+ int i;
+
+ /* We only check input reloads. */
+ if (! rld[r1].in || ! rld[r2].in)
+ return false;
+
+ /* Avoid anything with output reloads. */
+ if (rld[r1].out || rld[r2].out)
+ return false;
+
+ /* "chained" means one reload is a component of the other reload,
+ not the same as the other reload. */
+ if (rld[r1].opnum != rld[r2].opnum
+ || rtx_equal_p (rld[r1].in, rld[r2].in)
+ || rld[r1].optional || rld[r2].optional
+ || ! (reg_mentioned_p (rld[r1].in, rld[r2].in)
+ || reg_mentioned_p (rld[r2].in, rld[r1].in)))
+ return false;
+
+ for (i = 0; i < n_reloads; i ++)
+ /* Look for input reloads that aren't our two */
+ if (i != r1 && i != r2 && rld[i].in)
+ {
+ /* If our reload is mentioned at all, it isn't a simple chain. */
+ if (reg_mentioned_p (rld[r1].in, rld[i].in))
+ return false;
+ }
+ return true;
+}
+
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