[Ada] Copy index expression trees rather than relocating them

2018-05-28  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* exp_aggr.adb (Flatten): Copy tree of expression in a component
	association with a range or a set of discrete choices, rather than
	relocating the node. This avoids inconsistencies in the tree when
	handling nested subprograms with uplevel references for LLVM.

From-SVN: r260829

gcc/ada/ChangeLog

+2018-05-28  Ed Schonberg  <schonberg@adacore.com>
+
+	* exp_aggr.adb (Flatten): Copy tree of expression in a component
+	association with a range or a set of discrete choices, rather than
+	relocating the node. This avoids inconsistencies in the tree when
+	handling nested subprograms with uplevel references for LLVM.
+
 2018-05-28  Arnaud Charlet  <charlet@adacore.com>
 
 	* exp_util.adb (Possible_Bit_Aligned_Component): Always return False in

gcc/ada/exp_aggr.adb

@@ -4490,7 +4490,9 @@ package body Exp_Aggr is
                      return False;
                   end if;
 
-                  Vals (Num) := Relocate_Node (Elmt);
+                  --  Duplicate expression for each index it covers.
+
+                  Vals (Num) := New_Copy_Tree (Elmt);
                   Num := Num + 1;
 
                   Next (Elmt);