From 25d74b98caeaae881e374924886ee664aa1af5bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=83=91=E6=99=A8=E5=8D=89?= <zhengchenhui1@huawei.com>
Date: Mon, 9 Oct 2023 14:41:01 +0800
Subject: [PATCH 22/26] [DFE]Fix unexpected struct function pointer elimination
 bug.

---
 gcc/ipa-struct-reorg/ipa-struct-reorg.c    |  9 ++-
 gcc/testsuite/gcc.dg/struct/dfe_func_ptr.c | 69 ++++++++++++++++++++++
 2 files changed, 76 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_func_ptr.c

diff --git a/gcc/ipa-struct-reorg/ipa-struct-reorg.c b/gcc/ipa-struct-reorg/ipa-struct-reorg.c
index 367bcf210..fe99e8733 100644
--- a/gcc/ipa-struct-reorg/ipa-struct-reorg.c
+++ b/gcc/ipa-struct-reorg/ipa-struct-reorg.c
@@ -438,7 +438,11 @@ srtype::has_dead_field (void)
   unsigned i;
   FOR_EACH_VEC_ELT (fields, i, this_field)
     {
-      if (!(this_field->field_access & READ_FIELD))
+      /* Function pointer members are not processed, because DFE
+         does not currently support accurate analysis of function
+         pointers, and we have not identified specific use cases. */
+      if (!(this_field->field_access & READ_FIELD)
+	 && !FUNCTION_POINTER_TYPE_P (this_field->fieldtype))
 	{
 	  may_dfe = true;
 	  break;
@@ -1024,7 +1028,8 @@ srtype::create_new_type (void)
     {
       srfield *f = fields[i];
       if (current_layout_opt_level & DEAD_FIELD_ELIMINATION
-	  && !(f->field_access & READ_FIELD))
+	  && !(f->field_access & READ_FIELD)
+	  && !FUNCTION_POINTER_TYPE_P (f->fieldtype))
 	continue;
       f->create_new_fields (newtype, newfields, newlast);
     }
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_func_ptr.c b/gcc/testsuite/gcc.dg/struct/dfe_func_ptr.c
new file mode 100644
index 000000000..74ea93bbc
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_func_ptr.c
@@ -0,0 +1,69 @@
+/* { dg-do compile } */
+/* { dg-do run } */
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#ifdef STACK_SIZE
+#if STACK_SIZE > 16000
+#define N 1000
+#else
+#define N (STACK_SIZE/16)
+#endif
+#else
+#define N 1000
+#endif
+
+int num;
+
+int (*foo)(int d);
+int f (int t);
+
+typedef struct str_t str_t1;
+struct str_t
+{
+   int a;
+   float b;
+   int (*foo)(int d);
+};
+
+int main ()
+{
+   int i, r;
+   r = rand ();
+   num = r > N ? N : r;
+   str_t1 * p1 = calloc (num, sizeof (str_t1));
+   if (p1 == NULL)
+      return 0;
+   for (i = 0; i < num; i++)
+     {
+       p1[i].foo = malloc (1 * sizeof (f));
+       p1[i].foo = f;
+       p1[i].foo (i);
+     }
+
+   for (i = 0; i < num; i++)
+      p1[i].a = 1;
+
+   for (i = 0; i < num; i++)
+      p1[i].b = 2;
+
+   for (i = 0; i < num; i++)
+      if (p1[i].a != 1)
+	 abort ();
+
+   for (i = 0; i < num; i++)
+      if (abs (p1[i].b - 2) > 0.0001)
+	 abort ();
+
+   return 0;
+}
+
+int f (int t)
+{
+   if ( t < 0)
+      abort ();
+   return 0;
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 0 "struct_reorg" } } */
-- 
2.27.0