From: Robert Dewar <dewar@adacore.com>
Date: Thu, 13 Dec 2007 10:23:01 +0000 (+0100)
Subject: checks.adb: Fix optimization problem with short-circuited form
X-Git-Tag: releases/gcc-4.3.0~1073
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=16a55e63a98590ef71a37ff61c828c6b16bd75fb;p=thirdparty%2Fgcc.git

checks.adb: Fix optimization problem with short-circuited form

2007-12-06  Robert Dewar  <dewar@adacore.com>

	* checks.adb: Fix optimization problem with short-circuited form

From-SVN: r130823
---

diff --git a/gcc/ada/checks.adb b/gcc/ada/checks.adb
index f9f0c1041bf9..739559463216 100644
--- a/gcc/ada/checks.adb
+++ b/gcc/ada/checks.adb
@@ -2501,20 +2501,45 @@ package body Checks is
          P := Parent (N);
          K := Nkind (P);
 
-         if K not in N_Subexpr then
+         --  Done if out of subexpression (note that we allow generated stuff
+         --  such as itype declarations in this context, to keep the loop going
+         --  since we may well have generated such stuff in complex situations.
+         --  Also done if no parent (probably an error condition, but no point
+         --  in behaving nasty if we find it!)
+
+         if No (P)
+           or else (K not in N_Subexpr and then Comes_From_Source (P))
+         then
             return True;
 
-         --  Or/Or Else case, left operand must be equality test
+         --  Or/Or Else case, where test is part of the right operand, or is
+         --  part of one of the actions associated with the right operand, and
+         --  the left operand is an equality test.
 
-         elsif K = N_Op_Or or else K = N_Or_Else then
+         elsif K = N_Op_Or then
             exit when N = Right_Opnd (P)
               and then Nkind (Left_Opnd (P)) = N_Op_Eq;
 
-         --  And/And then case, left operand must be inequality test
+         elsif K = N_Or_Else then
+            exit when (N = Right_Opnd (P)
+                        or else
+                          (Is_List_Member (N)
+                             and then List_Containing (N) = Actions (P)))
+              and then Nkind (Left_Opnd (P)) = N_Op_Eq;
 
-         elsif K = N_Op_And or else K = N_And_Then then
+         --  Similar test for the And/And then case, where the left operand
+         --  is an inequality test.
+
+         elsif K = N_Op_And then
             exit when N = Right_Opnd (P)
               and then Nkind (Left_Opnd (P)) = N_Op_Ne;
+
+         elsif K = N_And_Then then
+            exit when (N = Right_Opnd (P)
+                        or else
+                          (Is_List_Member (N)
+                             and then List_Containing (N) = Actions (P)))
+              and then Nkind (Left_Opnd (P)) = N_Op_Ne;
          end if;
 
          N := P;
@@ -2524,11 +2549,6 @@ package body Checks is
       --  appropriate test as its left operand. So test further.
 
       L := Left_Opnd (P);
-
-      if Nkind (L) = N_Op_Not then
-         L := Right_Opnd (L);
-      end if;
-
       R := Right_Opnd (L);
       L := Left_Opnd (L);