(reload): If only non-group need is unfilled, see if

regs spilled for earlier classes can satisfy it.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@4597 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/reload1.c b/gcc/reload1.c
index 8d3dd85..0881342 100644 (file)
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -1785,6 +1785,35 @@ reload (first, global, dumpfile)
 
          while (max_needs[class] > 0 || max_nongroups[class] > 0)
            {
+#ifdef SMALL_REGISTER_CLASSES
+             /* This should be right for all machines, but only the 386
+                is known to need it, so this conditional plays safe.
+                ??? For 2.5, try making this unconditional.  */
+             /* If we spilled enough regs, but they weren't counted
+                against the non-group need, see if we can count them now.
+                If so, we can avoid some actual spilling.  */
+             if (max_needs[class] <= 0 && max_nongroups[class] > 0)
+               for (i = 0; i < n_spills; i++)
+                 if (TEST_HARD_REG_BIT (reg_class_contents[class],
+                                        spill_regs[i])
+                     && !TEST_HARD_REG_BIT (counted_for_groups,
+                                            spill_regs[i])
+                     && !TEST_HARD_REG_BIT (counted_for_nongroups,
+                                            spill_regs[i])
+                     && max_nongroups[class] > 0)
+                   {
+                     register enum reg_class *p;
+
+                     SET_HARD_REG_BIT (counted_for_nongroups, spill_regs[i]);
+                     max_nongroups[class]--;
+                     p = reg_class_superclasses[class];
+                     while (*p != LIM_REG_CLASSES)
+                       max_nongroups[(int) *p++]--;
+                   }
+             if (max_needs[class] <= 0 && max_nongroups[class] <= 0)
+               break;
+#endif
+
              /* Consider the potential reload regs that aren't
                 yet in use as reload regs, in order of preference.
                 Find the most preferred one that's in this class.  */