Expand comment for tree_niter_desc.max

This requirement is enforced by a gcc_checking_assert in
record_estimate.

gcc/ChangeLog:

	* tree-ssa-loop.h (tree_niter_desc): Update comment.

diff --git a/gcc/tree-ssa-loop.h b/gcc/tree-ssa-loop.h
index 6c70f79..c24215b 100644 (file)
--- a/gcc/tree-ssa-loop.h
+++ b/gcc/tree-ssa-loop.h
@@ -52,7 +52,8 @@ public:
                           may_be_zero == false), more precisely the number
                           of executions of the latch of the loop.  */
   widest_int max;      /* The upper bound on the number of iterations of
-                          the loop.  */
+                          the loop.  If niter is constant, then these values
+                          must agree.  */
 
   /* The simplified shape of the exit condition.  This information is used by
      loop unrolling.  If CMP is ERROR_MARK, then the loop cannot be unrolled.