(reload) [SMALL_REGISTER_CLASSES]: Try, at least,

to avoid 2-groups whose second register is explicitly used.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@6047 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/reload1.c b/gcc/reload1.c
index 33f118b..542c9d7 100644 (file)
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -1695,6 +1695,34 @@ reload (first, global, dumpfile)
                        }
                    }
                  /* We can't complete a group, so start one.  */
+#ifdef SMALL_REGISTER_CLASSES
+                 /* Look for a pair neither of which is explicitly used.  */
+                 if (i == FIRST_PSEUDO_REGISTER)
+                   for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+                     {
+                       int k;
+                       j = potential_reload_regs[i];
+                       /* Verify that J+1 is a potential reload reg.  */
+                       for (k = 0; k < FIRST_PSEUDO_REGISTER; k++)
+                         if (potential_reload_regs[k] == j + 1)
+                           break;
+                       if (j >= 0 && j + 1 < FIRST_PSEUDO_REGISTER
+                           && k < FIRST_PSEUDO_REGISTER
+                           && spill_reg_order[j] < 0 && spill_reg_order[j + 1] < 0
+                           && TEST_HARD_REG_BIT (reg_class_contents[class], j)
+                           && TEST_HARD_REG_BIT (reg_class_contents[class], j + 1)
+                           && HARD_REGNO_MODE_OK (j, group_mode[class])
+                           && ! TEST_HARD_REG_BIT (counted_for_nongroups,
+                                                   j + 1)
+                           && ! TEST_HARD_REG_BIT (bad_spill_regs, j + 1)
+                           /* Reject J at this stage
+                              if J+1 was explicitly used.  */
+                           && ! regs_explicitly_used[j + 1])
+                         break;
+                     }
+#endif
+                 /* Now try any group at all
+                    whose registers are not in bad_spill_regs.  */
                  if (i == FIRST_PSEUDO_REGISTER)
                    for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
                      {