[gcc r12-3784] Small tweak to comments in range_cannot_be_superflat

[Eric Botcazou <ebotcazou@gcc.gnu.org>]

https://gcc.gnu.org/g:3ae5e6fbc89f45ef6874c3d37b75ae63311943a3

commit r12-3784-g3ae5e6fbc89f45ef6874c3d37b75ae63311943a3
Author: Eric Botcazou <ebotcazou@adacore.com>
Date:   Wed Sep 22 12:18:48 2021 +0200

    Small tweak to comments in range_cannot_be_superflat
    
    gcc/ada/
            * gcc-interface/decl.c (range_cannot_be_superflat): Tweak comments.

Diff:
---
 gcc/ada/gcc-interface/decl.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
index 884d1d8fce3..32142d05764 100644
--- a/gcc/ada/gcc-interface/decl.c
+++ b/gcc/ada/gcc-interface/decl.c
@@ -6503,7 +6503,8 @@ range_cannot_be_superflat (Node_Id gnat_range)
   Node_Id gnat_scalar_range;
   tree gnu_lb, gnu_hb, gnu_lb_minus_one;
 
-  /* If the low bound is not constant, try to find an upper bound.  */
+  /* If the low bound is not constant, take the worst case by finding an upper
+     bound for its type, repeatedly if need be.  */
   while (Nkind (gnat_lb) != N_Integer_Literal
 	 && (Ekind (Etype (gnat_lb)) == E_Signed_Integer_Subtype
 	     || Ekind (Etype (gnat_lb)) == E_Modular_Integer_Subtype)
@@ -6512,7 +6513,8 @@ range_cannot_be_superflat (Node_Id gnat_range)
 	     || Nkind (gnat_scalar_range) == N_Range))
     gnat_lb = High_Bound (gnat_scalar_range);
 
-  /* If the high bound is not constant, try to find a lower bound.  */
+  /* If the high bound is not constant, take the worst case by finding a lower
+     bound for its type, repeatedly if need be.  */
   while (Nkind (gnat_hb) != N_Integer_Literal
 	 && (Ekind (Etype (gnat_hb)) == E_Signed_Integer_Subtype
 	     || Ekind (Etype (gnat_hb)) == E_Modular_Integer_Subtype)