Index: gcc/ira-conflicts.c
===================================================================
--- gcc.orig/ira-conflicts.c
+++ gcc/ira-conflicts.c
@@ -54,10 +54,10 @@ static IRA_INT_TYPE **conflicts;
 #define CONFLICT_ALLOCNO_P(A1, A2)					\
   (ALLOCNO_MIN (A1) <= ALLOCNO_CONFLICT_ID (A2)				\
    && ALLOCNO_CONFLICT_ID (A2) <= ALLOCNO_MAX (A1)			\
-   && TEST_ALLOCNO_SET_BIT (conflicts[ALLOCNO_NUM (A1)],		\
-	  		    ALLOCNO_CONFLICT_ID (A2),			\
-			    ALLOCNO_MIN (A1),				\
-			    ALLOCNO_MAX (A1)))
+   && TEST_MINMAX_SET_BIT (conflicts[ALLOCNO_NUM (A1)],			\
+			   ALLOCNO_CONFLICT_ID (A2),			\
+			   ALLOCNO_MIN (A1),				\
+			   ALLOCNO_MAX (A1)))
 
 
 
@@ -142,13 +142,13 @@ build_conflict_bit_table (void)
 		  /* Don't set up conflict for the allocno with itself.  */
 		  && num != (int) j)
 		{
-		  SET_ALLOCNO_SET_BIT (conflicts[num],
-				       ALLOCNO_CONFLICT_ID (live_a),
-				       ALLOCNO_MIN (allocno),
-				       ALLOCNO_MAX (allocno));
-		  SET_ALLOCNO_SET_BIT (conflicts[j], id,
-				       ALLOCNO_MIN (live_a),
-				       ALLOCNO_MAX (live_a));
+		  SET_MINMAX_SET_BIT (conflicts[num],
+				      ALLOCNO_CONFLICT_ID (live_a),
+				      ALLOCNO_MIN (allocno),
+				      ALLOCNO_MAX (allocno));
+		  SET_MINMAX_SET_BIT (conflicts[j], id,
+				      ALLOCNO_MIN (live_a),
+				      ALLOCNO_MAX (live_a));
 		}
 	    }
 	}
@@ -569,12 +569,12 @@ build_allocno_conflicts (ira_allocno_t a
   ira_allocno_t parent_a, another_a, another_parent_a;
   ira_allocno_t *vec;
   IRA_INT_TYPE *allocno_conflicts;
-  ira_allocno_set_iterator asi;
+  minmax_set_iterator asi;
 
   allocno_conflicts = conflicts[ALLOCNO_NUM (a)];
   px = 0;
-  FOR_EACH_ALLOCNO_IN_SET (allocno_conflicts,
-			   ALLOCNO_MIN (a), ALLOCNO_MAX (a), i, asi)
+  FOR_EACH_BIT_IN_MINMAX_SET (allocno_conflicts,
+			      ALLOCNO_MIN (a), ALLOCNO_MAX (a), i, asi)
     {
       another_a = ira_conflict_id_allocno_map[i];
       ira_assert (ira_reg_classes_intersect_p
@@ -610,8 +610,8 @@ build_allocno_conflicts (ira_allocno_t a
   ira_assert (parent != NULL);
   ira_assert (ALLOCNO_COVER_CLASS (a) == ALLOCNO_COVER_CLASS (parent_a));
   parent_num = ALLOCNO_NUM (parent_a);
-  FOR_EACH_ALLOCNO_IN_SET (allocno_conflicts,
-			   ALLOCNO_MIN (a), ALLOCNO_MAX (a), i, asi)
+  FOR_EACH_BIT_IN_MINMAX_SET (allocno_conflicts,
+			      ALLOCNO_MIN (a), ALLOCNO_MAX (a), i, asi)
     {
       another_a = ira_conflict_id_allocno_map[i];
       ira_assert (ira_reg_classes_intersect_p
@@ -623,10 +623,10 @@ build_allocno_conflicts (ira_allocno_t a
       ira_assert (ALLOCNO_NUM (another_parent_a) >= 0);
       ira_assert (ALLOCNO_COVER_CLASS (another_a)
 		  == ALLOCNO_COVER_CLASS (another_parent_a));
-      SET_ALLOCNO_SET_BIT (conflicts[parent_num],
-			   ALLOCNO_CONFLICT_ID (another_parent_a),
-			   ALLOCNO_MIN (parent_a),
-			   ALLOCNO_MAX (parent_a));
+      SET_MINMAX_SET_BIT (conflicts[parent_num],
+			  ALLOCNO_CONFLICT_ID (another_parent_a),
+			  ALLOCNO_MIN (parent_a),
+			  ALLOCNO_MAX (parent_a));
     }
 }
 
Index: gcc/ira-int.h
===================================================================
--- gcc.orig/ira-int.h
+++ gcc/ira-int.h
@@ -567,10 +567,16 @@ extern int ira_move_loops_num, ira_addit
 
 /* Maximal value of element of array ira_reg_class_nregs.  */
 extern int ira_max_nregs;
+
+/* This page contains a bitset implementation called 'min/max sets' used to
+   record conflicts in IRA.
+   They are named min/maxs set since we keep track of a minimum and a maximum
+   bit number for each set representing the bounds of valid elements.  Otherwise,
+   the implementation resembles sbitmaps in that we store an array of integers
+   whose bits directly represent the members of the set.  */
 
-/* The number of bits in each element of array used to implement a bit
-   vector of allocnos and what type that element has.  We use the
-   largest integer format on the host machine.  */
+/* The type used as elements in the array, and the number of bits in
+   this type.  */
 #define IRA_INT_BITS HOST_BITS_PER_WIDE_INT
 #define IRA_INT_TYPE HOST_WIDE_INT
 
@@ -579,7 +585,7 @@ extern int ira_max_nregs;
    MAX.  */
 #if defined ENABLE_IRA_CHECKING && (GCC_VERSION >= 2007)
 
-#define SET_ALLOCNO_SET_BIT(R, I, MIN, MAX) __extension__	        \
+#define SET_MINMAX_SET_BIT(R, I, MIN, MAX) __extension__	        \
   (({ int _min = (MIN), _max = (MAX), _i = (I);				\
      if (_i < _min || _i > _max)					\
        {								\
@@ -592,7 +598,7 @@ extern int ira_max_nregs;
       |= ((IRA_INT_TYPE) 1 << ((unsigned) (_i - _min) % IRA_INT_BITS))); }))
 
 
-#define CLEAR_ALLOCNO_SET_BIT(R, I, MIN, MAX) __extension__	        \
+#define CLEAR_MINMAX_SET_BIT(R, I, MIN, MAX) __extension__	        \
   (({ int _min = (MIN), _max = (MAX), _i = (I);				\
      if (_i < _min || _i > _max)					\
        {								\
@@ -604,7 +610,7 @@ extern int ira_max_nregs;
      ((R)[(unsigned) (_i - _min) / IRA_INT_BITS]			\
       &= ~((IRA_INT_TYPE) 1 << ((unsigned) (_i - _min) % IRA_INT_BITS))); }))
 
-#define TEST_ALLOCNO_SET_BIT(R, I, MIN, MAX) __extension__	        \
+#define TEST_MINMAX_SET_BIT(R, I, MIN, MAX) __extension__	        \
   (({ int _min = (MIN), _max = (MAX), _i = (I);				\
      if (_i < _min || _i > _max)					\
        {								\
@@ -618,25 +624,24 @@ extern int ira_max_nregs;
 
 #else
 
-#define SET_ALLOCNO_SET_BIT(R, I, MIN, MAX)			\
+#define SET_MINMAX_SET_BIT(R, I, MIN, MAX)			\
   ((R)[(unsigned) ((I) - (MIN)) / IRA_INT_BITS]			\
    |= ((IRA_INT_TYPE) 1 << ((unsigned) ((I) - (MIN)) % IRA_INT_BITS)))
 
-#define CLEAR_ALLOCNO_SET_BIT(R, I, MIN, MAX)			\
+#define CLEAR_MINMAX_SET_BIT(R, I, MIN, MAX)			\
   ((R)[(unsigned) ((I) - (MIN)) / IRA_INT_BITS]			\
    &= ~((IRA_INT_TYPE) 1 << ((unsigned) ((I) - (MIN)) % IRA_INT_BITS)))
 
-#define TEST_ALLOCNO_SET_BIT(R, I, MIN, MAX)			\
+#define TEST_MINMAX_SET_BIT(R, I, MIN, MAX)			\
   ((R)[(unsigned) ((I) - (MIN)) / IRA_INT_BITS]			\
    & ((IRA_INT_TYPE) 1 << ((unsigned) ((I) - (MIN)) % IRA_INT_BITS)))
 
 #endif
 
-/* The iterator for allocno set implemented ed as allocno bit
-   vector.  */
+/* The iterator for min/max sets.  */
 typedef struct {
 
-  /* Array containing the allocno bit vector.  */
+  /* Array containing the bit vector.  */
   IRA_INT_TYPE *vec;
 
   /* The number of the current element in the vector.  */
@@ -653,13 +658,13 @@ typedef struct {
 
   /* The word of the bit vector currently visited.  */
   unsigned IRA_INT_TYPE word;
-} ira_allocno_set_iterator;
+} minmax_set_iterator;
 
-/* Initialize the iterator I for allocnos bit vector VEC containing
-   minimal and maximal values MIN and MAX.  */
+/* Initialize the iterator I for bit vector VEC containing minimal and
+   maximal values MIN and MAX.  */
 static inline void
-ira_allocno_set_iter_init (ira_allocno_set_iterator *i,
-			   IRA_INT_TYPE *vec, int min, int max)
+minmax_set_iter_init (minmax_set_iterator *i, IRA_INT_TYPE *vec, int min,
+		      int max)
 {
   i->vec = vec;
   i->word_num = 0;
@@ -669,11 +674,11 @@ ira_allocno_set_iter_init (ira_allocno_s
   i->word = i->nel == 0 ? 0 : vec[0];
 }
 
-/* Return TRUE if we have more allocnos to visit, in which case *N is
-   set to the allocno number to be visited.  Otherwise, return
+/* Return TRUE if we have more elements to visit, in which case *N is
+   set to the number of the element to be visited.  Otherwise, return
    FALSE.  */
 static inline bool
-ira_allocno_set_iter_cond (ira_allocno_set_iterator *i, int *n)
+minmax_set_iter_cond (minmax_set_iterator *i, int *n)
 {
   /* Skip words that are zeros.  */
   for (; i->word == 0; i->word = i->vec[i->word_num])
@@ -695,23 +700,23 @@ ira_allocno_set_iter_cond (ira_allocno_s
   return true;
 }
 
-/* Advance to the next allocno in the set.  */
+/* Advance to the next element in the set.  */
 static inline void
-ira_allocno_set_iter_next (ira_allocno_set_iterator *i)
+minmax_set_iter_next (minmax_set_iterator *i)
 {
   i->word >>= 1;
   i->bit_num++;
 }
 
-/* Loop over all elements of allocno set given by bit vector VEC and
+/* Loop over all elements of a min/max set given by bit vector VEC and
    their minimal and maximal values MIN and MAX.  In each iteration, N
    is set to the number of next allocno.  ITER is an instance of
-   ira_allocno_set_iterator used to iterate the allocnos in the set.  */
-#define FOR_EACH_ALLOCNO_IN_SET(VEC, MIN, MAX, N, ITER)		\
-  for (ira_allocno_set_iter_init (&(ITER), (VEC), (MIN), (MAX));	\
-       ira_allocno_set_iter_cond (&(ITER), &(N));			\
-       ira_allocno_set_iter_next (&(ITER)))
-
+   minmax_set_iterator used to iterate over the set.  */
+#define FOR_EACH_BIT_IN_MINMAX_SET(VEC, MIN, MAX, N, ITER)	\
+  for (minmax_set_iter_init (&(ITER), (VEC), (MIN), (MAX));	\
+       minmax_set_iter_cond (&(ITER), &(N));			\
+       minmax_set_iter_next (&(ITER)))
+
 /* ira.c: */
 
 /* Map: hard regs X modes -> set of hard registers for storing value
Index: gcc/ira-build.c
===================================================================
--- gcc.orig/ira-build.c
+++ gcc/ira-build.c
@@ -670,7 +670,7 @@ add_to_allocno_conflicts (ira_allocno_t 
 	    }
 	  ALLOCNO_MAX (a1) = id;
 	}
-      SET_ALLOCNO_SET_BIT (vec, id, ALLOCNO_MIN (a1), ALLOCNO_MAX (a1));
+      SET_MINMAX_SET_BIT (vec, id, ALLOCNO_MIN (a1), ALLOCNO_MAX (a1));
     }
 }