From 83a35da4910fc7d8f29ced3e0ff8adddeb537731 Mon Sep 17 00:00:00 2001
From: huangxiaoquan <huangxiaoquan1@huawei.com>
Date: Fri, 27 Aug 2021 14:53:18 +0800
Subject: [PATCH 23/24] [StructReorderFields] Add pointer offset check

The pointer offset check is added for the expr that is dereferenced
in the memory, and escapes struct pointer offset operations involving
field order.

diff --git a/gcc/ipa-struct-reorg/ipa-struct-reorg.c b/gcc/ipa-struct-reorg/ipa-struct-reorg.c
index 85986ce5803..b0d4fe80797 100644
--- a/gcc/ipa-struct-reorg/ipa-struct-reorg.c
+++ b/gcc/ipa-struct-reorg/ipa-struct-reorg.c
@@ -3876,6 +3876,17 @@ ipa_struct_reorg::get_type_field (tree expr, tree &base, bool &indirect,
       return false;
     }
 
+  /* Escape the operation of fetching field with pointer offset such as:
+     *(&(t->right)) = malloc (0); -> MEM[(struct node * *)_1 + 8B] = malloc (0);
+  */
+  if (current_mode != NORMAL
+      && (TREE_CODE (expr) == MEM_REF) && (offset != 0))
+    {
+      gcc_assert (can_escape);
+      t->mark_escape (escape_non_multiply_size, NULL);
+      return false;
+    }
+
   if (wholeaccess (expr, base, accesstype, t))
     {
       field = NULL;
diff --git a/gcc/testsuite/gcc.dg/struct/rf_ptr2void_lto.c b/gcc/testsuite/gcc.dg/struct/rf_ptr2void_lto.c
index 190b9418275..2ae46fb3112 100644
--- a/gcc/testsuite/gcc.dg/struct/rf_ptr2void_lto.c
+++ b/gcc/testsuite/gcc.dg/struct/rf_ptr2void_lto.c
@@ -84,4 +84,4 @@ main ()
   return cnt;
 }
 
-/* { dg-final { scan-ipa-dump "Number of structures to transform is 1" "reorder_fields" } } */
\ No newline at end of file
+/* { dg-final { scan-ipa-dump "No structures to transform." "reorder_fields" } } */
\ No newline at end of file
diff --git a/gcc/testsuite/gcc.dg/struct/rf_ptr_offset.c b/gcc/testsuite/gcc.dg/struct/rf_ptr_offset.c
new file mode 100644
index 00000000000..317aafa5f72
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/rf_ptr_offset.c
@@ -0,0 +1,34 @@
+/* { dg-do compile } */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+struct node
+{
+    struct node *left, *right;
+    double a, b, c, d, e, f;
+}
+*a;
+int b, c;
+void
+CreateNode (struct node **p1)
+{
+    *p1 = calloc (10, sizeof (struct node));
+}
+
+int
+main ()
+{
+    a->left = 0;
+    struct node *t = a;
+    CreateNode (&t->right);
+
+    struct node p = *a;
+    b = 1;
+    if (p.left)
+        b = 0;
+    if (b)
+        printf ("   Tree.\n");
+}
+
+/* { dg-final { scan-ipa-dump "No structures to transform." "reorder_fields" } } */
\ No newline at end of file
-- 
2.21.0.windows.1