On 01-09-14 18:41, Ulrich Weigand wrote:
Tom de Vries wrote:
* ira-costs.c (ira_tune_allocno_costs): Use
ALLOCNO_CROSSED_CALLS_CLOBBERED_REGS to adjust costs.
In debugging PR 53864 on s390x-linux, I ran into a weird change in behavior
that occurs when the following part of this patch was checked in:
- if (ira_hard_reg_set_intersection_p (regno, mode,
call_used_reg_set)
- || HARD_REGNO_CALL_PART_CLOBBERED (regno, mode))
- cost += (ALLOCNO_CALL_FREQ (a)
- * (ira_memory_move_cost[mode][rclass][0]
- + ira_memory_move_cost[mode][rclass][1]));
+ crossed_calls_clobber_regs
+ = &(ALLOCNO_CROSSED_CALLS_CLOBBERED_REGS (a));
+ if (ira_hard_reg_set_intersection_p (regno, mode,
+ *crossed_calls_clobber_regs))
+ {
+ if (ira_hard_reg_set_intersection_p (regno, mode,
+ call_used_reg_set)
+ || HARD_REGNO_CALL_PART_CLOBBERED (regno, mode))
+ cost += (ALLOCNO_CALL_FREQ (a)
+ * (ira_memory_move_cost[mode][rclass][0]
+ + ira_memory_move_cost[mode][rclass][1]));
#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);
+ 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
+ }
Before that patch, this code would penalize all call-clobbered registers
(if the alloca is used across a call), and it would penalize *all* registers
in a target-dependent way if IRA_HARD_REGNO_ADD_COST_MULTIPLIER is defined;
the latter is completely independent of the presence of any calls.
However, after that patch, the IRA_HARD_REGNO_ADD_COST_MULTIPLIER penalty
is only applied for registers clobbered by calls in this function. This
seems a completely unrelated change, and looks just wrong to me ...
Was this done intentionally or is this just an oversight?
Ulrich,
thanks for noticing this. I agree, this looks wrong, and is probably an
oversight. [ It seems that s390 is the only target defining
IRA_HARD_REGNO_ADD_COST_MULTIPLIER, so this problem didn't show up on any other
target. ]
I think attached patch fixes it.
I've build the patch and ran the fuse-caller-save tests, and I'm currently
bootstrapping and reg-testing it on x86_64.
Can you check whether this patches fixes the issue for s390 ?
Thanks,
- Tom
Bye,
Ulrich
diff --git a/gcc/ira-costs.c b/gcc/ira-costs.c
index 774a958..57239f5 100644
--- a/gcc/ira-costs.c
+++ b/gcc/ira-costs.c
@@ -2217,21 +2217,19 @@ ira_tune_allocno_costs (void)
crossed_calls_clobber_regs
= &(ALLOCNO_CROSSED_CALLS_CLOBBERED_REGS (a));
if (ira_hard_reg_set_intersection_p (regno, mode,
- *crossed_calls_clobber_regs))
- {
- if (ira_hard_reg_set_intersection_p (regno, mode,
+ *crossed_calls_clobber_regs)
+ && (ira_hard_reg_set_intersection_p (regno, mode,
call_used_reg_set)
- || HARD_REGNO_CALL_PART_CLOBBERED (regno, mode))
- cost += (ALLOCNO_CALL_FREQ (a)
- * (ira_memory_move_cost[mode][rclass][0]
- + ira_memory_move_cost[mode][rclass][1]));
+ || HARD_REGNO_CALL_PART_CLOBBERED (regno, mode)))
+ cost += (ALLOCNO_CALL_FREQ (a)
+ * (ira_memory_move_cost[mode][rclass][0]
+ + ira_memory_move_cost[mode][rclass][1]));
#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);
+ 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;
else
--
1.9.1
