diff options
| -rw-r--r-- | gcc/local-alloc.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/gcc/local-alloc.c b/gcc/local-alloc.c index 1ba5b1ba31f..dba5fe5b141 100644 --- a/gcc/local-alloc.c +++ b/gcc/local-alloc.c @@ -65,6 +65,17 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "recog.h" #include "output.h" +/* Pseudos allocated here cannot be reallocated by global.c if the hard + register is used as a spill register. So we don't allocate such pseudos + here if their preferred class is likely to be used by spills. + + On most machines, the appropriate test is if the class has one + register, so we default to that. */ + +#ifndef CLASS_LIKELY_SPILLED_P +#define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1) +#endif + /* Next quantity number available for allocation. */ static int next_qty; @@ -329,11 +340,11 @@ alloc_qty_for_scratch (scratch, n, insn, insn_code_num, insn_number) break; } - /* If CLASS has only one register, don't allocate the SCRATCH here since + /* If CLASS has only a few registers, don't allocate the SCRATCH here since it will prevent that register from being used as a spill register. reload will do the allocation. */ - if (class == NO_REGS || reg_class_size[(int) class] == 1) + if (class == NO_REGS || CLASS_LIKELY_SPILLED_P (class)) return; #else /* REGISTER_CONSTRAINTS */ @@ -411,7 +422,7 @@ local_alloc () /* Determine which pseudo-registers can be allocated by local-alloc. In general, these are the registers used only in a single block and which only die once. However, if a register's preferred class has only - one entry, don't allocate this register here unless it is preferred + a few entries, don't allocate this register here unless it is preferred or nothing since retry_global_alloc won't be able to move it to GENERAL_REGS if a reload register of this class is needed. @@ -422,7 +433,7 @@ local_alloc () { if (reg_basic_block[i] >= 0 && reg_n_deaths[i] == 1 && (reg_alternate_class (i) == NO_REGS - || reg_class_size[(int) reg_preferred_class (i)] > 1)) + || ! CLASS_LIKELY_SPILLED_P (reg_preferred_class (i)))) reg_qty[i] = -2; else reg_qty[i] = -1; |
