re PR c/9516 (Internal error when using a big array)

        PR c/9516
        * expr.c (safe_from_p): Rearrange to avoid deep recursion in
        favour of looping and tail recursion for TREE_LIST and binops.

Co-Authored-By: Richard Henderson <rth@redhat.com>
From-SVN: r65363

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 351251363e130951224be34f27ef1b05851a0cd7..5f294afc926d12648fdd303b31691b3ce47372d4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2003-04-07  Christian Ehrhardt  <ehrhardt@mathematik.uni-ulm.de>
+            Richard Henderson  <rth@redhat.com>
+
+        PR c/9516
+        * expr.c (safe_from_p): Rearrange to avoid deep recursion in
+        favour of looping and tail recursion for TREE_LIST and binops.
+
 2003-04-08  Zdenek Dvorak  <rakdver@atrey.karlin.mff.cuni.cz>
 
        * loop.h (REGNO_FIRST_LUID, REGNO_LAST_LUID): Provide defaults

diff --git a/gcc/expr.c b/gcc/expr.c
index e9d0ee52c92c750fe423f837d04a206941b4f089..075de49f8198b932d8f2b85b92701d66f4ec2119 100644 (file)
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -6093,22 +6093,31 @@ safe_from_p (x, exp, top_p)
 
     case 'x':
       if (TREE_CODE (exp) == TREE_LIST)
-       return ((TREE_VALUE (exp) == 0
-                || safe_from_p (x, TREE_VALUE (exp), 0))
-               && (TREE_CHAIN (exp) == 0
-                   || safe_from_p (x, TREE_CHAIN (exp), 0)));
+       {
+         while (1)
+           {
+             if (TREE_VALUE (exp) && !safe_from_p (x, TREE_VALUE (exp), 0))
+               return 0;
+             exp = TREE_CHAIN (exp);
+             if (!exp)
+               return 1;
+             if (TREE_CODE (exp) != TREE_LIST)
+               return safe_from_p (x, exp, 0);
+           }
+       }
       else if (TREE_CODE (exp) == ERROR_MARK)
        return 1;       /* An already-visited SAVE_EXPR? */
       else
        return 0;
 
-    case '1':
-      return safe_from_p (x, TREE_OPERAND (exp, 0), 0);
-
     case '2':
     case '<':
-      return (safe_from_p (x, TREE_OPERAND (exp, 0), 0)
-             && safe_from_p (x, TREE_OPERAND (exp, 1), 0));
+      if (!safe_from_p (x, TREE_OPERAND (exp, 1), 0))
+       return 0;
+      /* FALLTHRU */
+
+    case '1':
+      return safe_from_p (x, TREE_OPERAND (exp, 0), 0);
 
     case 'e':
     case 'r':