diff options
Diffstat (limited to 'gcc/regclass.c')
| -rw-r--r-- | gcc/regclass.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/gcc/regclass.c b/gcc/regclass.c index 7b2d5b1..8a0bab1 100644 --- a/gcc/regclass.c +++ b/gcc/regclass.c @@ -811,7 +811,8 @@ struct costs /* Structure used to record preferences of given pseudo. */ struct reg_pref { - /* (enum reg_class) prefclass is the preferred class. */ + /* (enum reg_class) prefclass is the preferred class. May be + NO_REGS if no class is better than memory. */ char prefclass; /* altclass is a register class that we should use for allocating @@ -1314,6 +1315,10 @@ regclass (rtx f, int nregs) best = reg_class_subunion[(int) best][class]; } + /* If no register class is better than memory, use memory. */ + if (p->mem_cost < best_cost) + best = NO_REGS; + /* Record the alternate register class; i.e., a class for which every register in it is better than using memory. If adding a class would make a smaller class (i.e., no union of just those @@ -1524,7 +1529,7 @@ record_reg_classes (int n_alts, int n_ops, rtx *ops, to what we would add if this register were not in the appropriate class. */ - if (reg_pref) + if (reg_pref && reg_pref[REGNO (op)].prefclass != NO_REGS) alt_cost += (may_move_in_cost[mode] [(unsigned char) reg_pref[REGNO (op)].prefclass] @@ -1750,7 +1755,7 @@ record_reg_classes (int n_alts, int n_ops, rtx *ops, to what we would add if this register were not in the appropriate class. */ - if (reg_pref) + if (reg_pref && reg_pref[REGNO (op)].prefclass != NO_REGS) alt_cost += (may_move_in_cost[mode] [(unsigned char) reg_pref[REGNO (op)].prefclass] @@ -1836,7 +1841,8 @@ record_reg_classes (int n_alts, int n_ops, rtx *ops, int class; unsigned int nr; - if (regno >= FIRST_PSEUDO_REGISTER && reg_pref != 0) + if (regno >= FIRST_PSEUDO_REGISTER && reg_pref != 0 + && reg_pref[regno].prefclass != NO_REGS) { enum reg_class pref = reg_pref[regno].prefclass; |