[gcc r12-1521] [Ada] Do not generate an Itype_Reference node for slices in GNATprove mode

[Pierre-Marie de Rodat <pmderodat@gcc.gnu.org>]

https://gcc.gnu.org/g:3feba0a578c364e6ca44ad5f954a30dc55e98065

commit r12-1521-g3feba0a578c364e6ca44ad5f954a30dc55e98065
Author: Yannick Moy <moy@adacore.com>
Date:   Wed Mar 3 14:54:09 2021 +0100

    [Ada] Do not generate an Itype_Reference node for slices in GNATprove mode
    
    gcc/ada/
    
            * sem_res.adb (Set_Slice_Subtype): Revert special-case
            introduced previously, which is not needed as Itypes created for
            slices are precisely always used.

Diff:
---
 gcc/ada/sem_res.adb | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/gcc/ada/sem_res.adb b/gcc/ada/sem_res.adb
index 4377f91b7b5..3ca45691585 100644
--- a/gcc/ada/sem_res.adb
+++ b/gcc/ada/sem_res.adb
@@ -12607,10 +12607,9 @@ package body Sem_Res is
       --  the point where actions for the slice are analyzed). Note that this
       --  is different from freezing the itype immediately, which might be
       --  premature (e.g. if the slice is within a transient scope). This needs
-      --  to be done only if expansion is enabled, or in GNATprove mode to
-      --  capture the associated run-time exceptions if any.
+      --  to be done only if expansion is enabled.
 
-      elsif Expander_Active or GNATprove_Mode then
+      elsif Expander_Active then
          Ensure_Defined (Typ => Slice_Subtype, N => N);
       end if;
    end Set_Slice_Subtype;