1 files changed, 4 insertions, 1 deletions
diff --git a/gcc/tree.h b/gcc/tree.h
index 0f78e74..e2742bc 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -1304,13 +1304,14 @@ struct tree_exp GTY(())
 #define SSA_NAME_OCCURS_IN_ABNORMAL_PHI(NODE) \
     SSA_NAME_CHECK (NODE)->common.asm_written_flag
 
-
 /* Nonzero if this SSA_NAME expression is currently on the free list of
    SSA_NAMES.  Using NOTHROW_FLAG seems reasonably safe since throwing
    has no meaning for an SSA_NAME.  */
 #define SSA_NAME_IN_FREE_LIST(NODE) \
     SSA_NAME_CHECK (NODE)->common.nothrow_flag
 
+/* If NAME is equivalent to some other SSA_NAME or an invariant, then
+   return the equivalent SSA_NAME or invariant, else return NULL.  */
 #define SSA_NAME_EQUIV(NAME) __extension__ \
   ({  tree equiv = SSA_NAME_CHECK (NAME)->ssa_name.equiv; \
       if (equiv && TREE_CODE (equiv) == SSA_NAME) \
@@ -1318,6 +1319,8 @@ struct tree_exp GTY(())
       equiv; \
    })
 
+/* Record that NAME (an SSA_NAME) is equivalent to EQUIV.  */
+
 #define SET_SSA_NAME_EQUIV(NAME, EQUIV)\
    SSA_NAME_CHECK (NAME)->ssa_name.equiv = (EQUIV);