[gcc r12-6435] ira: Fix s390 build

[gcc r12-6435] ira: Fix s390 build

[Richard Sandiford]

https://gcc.gnu.org/g:a923fa6d3b0424cb0eb50de49877515e802c4cb0

commit r12-6435-ga923fa6d3b0424cb0eb50de49877515e802c4cb0
Author: Richard Sandiford <richard.sandiford@arm.com>
Date:   Tue Jan 11 12:47:05 2022 +0000

    ira: Fix s390 build
    
    My g:01f3e6a40e7202310abbeb41c345d325bd69554f broke the s390
    build because the rclass variable was still needed by the
    IRA_HARD_REGNO_ADD_COST_MULTIPLIER code.
    
    gcc/
            * ira-costs.c (ira_tune_allocno_costs): Fix missing rclass
            definition in IRA_HARD_REGNO_ADD_COST_MULTIPLIER code.

Diff:
---
 gcc/ira-costs.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/gcc/ira-costs.c b/gcc/ira-costs.c
index cbb58d32be8..1e4cf5a35e4 100644
--- a/gcc/ira-costs.c
+++ b/gcc/ira-costs.c
@@ -2351,10 +2351,13 @@ ira_tune_allocno_costs (void)
 	      if (ira_need_caller_save_p (a, regno))
 		cost += ira_caller_save_cost (a);
 #ifdef IRA_HARD_REGNO_ADD_COST_MULTIPLIER
-	      cost += ((ira_memory_move_cost[mode][rclass][0]
-			+ ira_memory_move_cost[mode][rclass][1])
-		       * ALLOCNO_FREQ (a)
-		       * IRA_HARD_REGNO_ADD_COST_MULTIPLIER (regno) / 2);
+	      {
+		auto rclass = REGNO_REG_CLASS (regno);
+		cost += ((ira_memory_move_cost[mode][rclass][0]
+			  + ira_memory_move_cost[mode][rclass][1])
+			 * ALLOCNO_FREQ (a)
+			 * IRA_HARD_REGNO_ADD_COST_MULTIPLIER (regno) / 2);
+	      }
 #endif
 	      if (INT_MAX - cost < reg_costs[j])
 		reg_costs[j] = INT_MAX;