[COMMITTED] ada: Add missing guards in Selected_Range_Checks

[Marc Poulhiès]

From: Eric Botcazou <ebotcazou@adacore.com>

gcc/ada/

	* checks.adb (Selected_Range_Checks): Add guards to protect calls
	to Expr_Value on bounds.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/checks.adb | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gcc/ada/checks.adb b/gcc/ada/checks.adb
index 0d472964ff5..6525982aef9 100644
--- a/gcc/ada/checks.adb
+++ b/gcc/ada/checks.adb
@@ -10826,6 +10826,8 @@ package body Checks is
 
                if not Check_Added
                  and then Is_Fixed_Lower_Bound_Index_Subtype (T_Typ)
+                 and then Known_LB
+                 and then Known_T_LB
                  and then Expr_Value (LB) /= Expr_Value (T_LB)
                then
                   Add_Check
-- 
2.40.0