2011-10-12 Richard Guenther <rguenther@suse.de>

	PR tree-optimization/50700
	* tree-object-size.c (addr_object_size): Simplify and treat
	MEM_REF bases consistently.

	* gcc.dg/builtin-object-size-12.c: New testcase.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@179850 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 07e73ea..6bc0bd6 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2011-10-12  Richard Guenther  <rguenther@suse.de>
+
+       PR tree-optimization/50700
+       * tree-object-size.c (addr_object_size): Simplify and treat
+       MEM_REF bases consistently.
+
 2011-10-12  Bernd Schmidt  <bernds@codesourcery.com>
 
        * function.c (prepare_shrink_wrap, bb_active_p): New function.

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 70f89f9..827aa2d 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-10-12  Richard Guenther  <rguenther@suse.de>
+
+       PR tree-optimization/50700
+       * gcc.dg/builtin-object-size-12.c: New testcase.
+
 2011-10-12  Joseph Myers  <joseph@codesourcery.com>
 
        PR c/50565

diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-12.c b/gcc/testsuite/gcc.dg/builtin-object-size-12.c
new file mode 100644 (file)
index 0000000..b21eb00
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/builtin-object-size-12.c
@@ -0,0 +1,19 @@
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+extern void abort (void);
+struct S {
+    int len;
+    char s[0];
+};
+int main()
+{
+  char buf[sizeof (struct S) + 32];
+  if (__builtin_object_size (((struct S *)&buf[0])->s, 1) != 32)
+    abort ();
+  if (__builtin_object_size (((struct S *)&buf[1])->s, 1) != 31)
+    abort ();
+  if (__builtin_object_size (((struct S *)&buf[64])->s, 0) != 0)
+    abort ();
+  return 0;
+}

diff --git a/gcc/tree-object-size.c b/gcc/tree-object-size.c
index 2998fb5..017f8c5 100644 (file)
--- a/gcc/tree-object-size.c
+++ b/gcc/tree-object-size.c
@@ -166,24 +166,19 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
   gcc_assert (TREE_CODE (ptr) == ADDR_EXPR);
 
   pt_var = TREE_OPERAND (ptr, 0);
-  if (REFERENCE_CLASS_P (pt_var))
-    pt_var = get_base_address (pt_var);
+  while (handled_component_p (pt_var))
+    pt_var = TREE_OPERAND (pt_var, 0);
 
   if (pt_var
-      && TREE_CODE (pt_var) == MEM_REF
-      && TREE_CODE (TREE_OPERAND (pt_var, 0)) == SSA_NAME
-      && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (pt_var, 0))))
+      && TREE_CODE (pt_var) == MEM_REF)
     {
       unsigned HOST_WIDE_INT sz;
 
-      if (!osi || (object_size_type & 1) != 0)
+      if (!osi || (object_size_type & 1) != 0
+         || TREE_CODE (pt_var) != SSA_NAME)
        {
          sz = compute_builtin_object_size (TREE_OPERAND (pt_var, 0),
                                            object_size_type & ~1);
-         if (host_integerp (TREE_OPERAND (pt_var, 1), 0))
-           sz -= TREE_INT_CST_LOW (TREE_OPERAND (pt_var, 1));
-         else
-           sz = offset_limit;
        }
       else
        {
@@ -195,10 +190,17 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
            sz = object_sizes[object_size_type][SSA_NAME_VERSION (var)];
          else
            sz = unknown[object_size_type];
-         if (host_integerp (TREE_OPERAND (pt_var, 1), 0))
-           sz -= TREE_INT_CST_LOW (TREE_OPERAND (pt_var, 1));
+       }
+      if (sz != unknown[object_size_type])
+       {
+         double_int dsz = double_int_sub (uhwi_to_double_int (sz),
+                                          mem_ref_offset (pt_var));
+         if (double_int_negative_p (dsz))
+           sz = 0;
+         else if (double_int_fits_in_uhwi_p (dsz))
+           sz = double_int_to_uhwi (dsz);
          else
-           sz = offset_limit;
+           sz = unknown[object_size_type];
        }
 
       if (sz != unknown[object_size_type] && sz < offset_limit)
@@ -211,7 +213,7 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
                tree_low_cst (DECL_SIZE_UNIT (pt_var), 1) < offset_limit)
     pt_var_size = DECL_SIZE_UNIT (pt_var);
   else if (pt_var
-          && (SSA_VAR_P (pt_var) || TREE_CODE (pt_var) == STRING_CST)
+          && TREE_CODE (pt_var) == STRING_CST
           && TYPE_SIZE_UNIT (TREE_TYPE (pt_var))
           && host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (pt_var)), 1)
           && (unsigned HOST_WIDE_INT)