re PR tree-optimization/23929 (segfault in expand_simple_operations, tree-ssa-loop-niter.c:637)

PR tree-optimization/23929
	* tree-ssa-loop-niter.c (expand_simple_operations): Return immediately
	if expr is NULL.

	* gcc.c-torture/compile/pr23929.c: New test.

From-SVN: r104461

gcc/ChangeLog

@@ -1,5 +1,9 @@
 2005-09-20  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/23929
+	* tree-ssa-loop-niter.c (expand_simple_operations): Return immediately
+	if expr is NULL.
+
 	PR tree-optimization/23818
 	* tree-stdarg.c (execute_optimize_stdarg): Call
 	calculate_dominance_info.

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2005-09-20  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/23929
+	* gcc.c-torture/compile/pr23929.c: New test.
+
 2005-09-20  Steve Ellcey  <sje@cup.hp.com>
 
 	PR testsuite/23186

gcc/testsuite/gcc.c-torture/compile/pr23929.c

@@ -0,0 +1,21 @@
+/* PR tree-optimization/23929 */
+
+extern void bar (char *);
+
+void
+foo (int n, char *z)
+{
+  char b[2048];
+  int x, y;
+
+  bar (b);
+  for (y = 0; y < 60; y++)
+    if (n == 600)
+      for (x = 0; x < 320;)
+	{
+	  *z++ = b[x];
+	  x += 1;
+	  *z++ = b[x];
+	  x += 1;
+	}
+}

gcc/tree-ssa-loop-niter.c

@@ -634,11 +634,15 @@ expand_simple_operations (tree expr)
 {
   unsigned i, n;
   tree ret = NULL_TREE, e, ee, stmt;
-  enum tree_code code = TREE_CODE (expr);
+  enum tree_code code;
+
+  if (expr == NULL_TREE)
+    return expr;
 
   if (is_gimple_min_invariant (expr))
     return expr;
 
+  code = TREE_CODE (expr);
   if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
     {
       n = TREE_CODE_LENGTH (code);