From: Viljar Indus <indus@adacore.com>
Date: Tue, 12 Dec 2023 15:03:13 +0000 (+0200)
Subject: ada: Do not count comparison of addresses as a modification
X-Git-Tag: basepoints/gcc-15~3079
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9b7d674fadd07aed242711e91232dbd049ef35be;p=thirdparty%2Fgcc.git

ada: Do not count comparison of addresses as a modification

In some extended code we generate comparisons between
the Addresses of some variables. This causes those
variables to be considered modified. Whereas in this
particular scenario the variables are just referenced.

gcc/ada/

	* sem_attr.adb: avoid marking a use of the Address attribute
	as a modification of its prefix.
---

diff --git a/gcc/ada/sem_attr.adb b/gcc/ada/sem_attr.adb
index a194360a6013..f52103f28ddc 100644
--- a/gcc/ada/sem_attr.adb
+++ b/gcc/ada/sem_attr.adb
@@ -12133,9 +12133,13 @@ package body Sem_Attr is
             | Attribute_Code_Address
          =>
             --  To be safe, assume that if the address of a variable is taken,
-            --  it may be modified via this address, so note modification.
+            --  it may be modified via this address, so note modification,
+            --  unless the address is compared directly, which should not be
+            --  considered a modification.
 
-            if Is_Variable (P) then
+            if Is_Variable (P)
+              and then Nkind (Parent (N)) not in N_Op_Compare
+            then
                Note_Possible_Modification (P, Sure => False);
             end if;