reload: Adjust comment in find_reloads about subset, not intersection

gcc:
	* reload.cc (find_reloads): Align comment with code where
	considering the intersection of register classes then tweaking the
	regclass for the current alternative or rejecting it.

diff --git a/gcc/reload.cc b/gcc/reload.cc
index 664082a533d9bd0e91f77c5abb4d9af1f48b0114..3ed901e3944702e8134e829269670231a4c28ce9 100644 (file)
--- a/gcc/reload.cc
+++ b/gcc/reload.cc
@@ -3635,9 +3635,11 @@ find_reloads (rtx_insn *insn, int replace, int ind_levels, int live_known,
                 a hard reg and this alternative accepts some
                 register, see if the class that we want is a subset
                 of the preferred class for this register.  If not,
-                but it intersects that class, use the preferred class
-                instead.  If it does not intersect the preferred
-                class, show that usage of this alternative should be
+                but it intersects that class, we'd like to use the
+                intersection, but the best we can do is to use the
+                preferred class, if it is instead a subset of the
+                class we want in this alternative.  If we can't use
+                it, show that usage of this alternative should be
                 discouraged; it will be discouraged more still if the
                 register is `preferred or nothing'.  We do this
                 because it increases the chance of reusing our spill
@@ -3664,9 +3666,10 @@ find_reloads (rtx_insn *insn, int replace, int ind_levels, int live_known,
                  if (! reg_class_subset_p (this_alternative[i],
                                            preferred_class[i]))
                    {
-                     /* Since we don't have a way of forming the intersection,
-                        we just do something special if the preferred class
-                        is a subset of the class we have; that's the most
+                     /* Since we don't have a way of forming a register
+                        class for the intersection, we just do
+                        something special if the preferred class is a
+                        subset of the class we have; that's the most
                         common case anyway.  */
                      if (reg_class_subset_p (preferred_class[i],
                                              this_alternative[i]))