From: Richard Biener <rguenther@suse.de>
Date: Fri, 10 Sep 2021 08:17:24 +0000 (+0200)
Subject: middle-end/102269 - avoid auto-init of empty types
X-Git-Tag: basepoints/gcc-13~4868
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1dae802b685937b1dc52e49d0641c75f3186ba14;p=thirdparty%2Fgcc.git

middle-end/102269 - avoid auto-init of empty types

This avoids initializing empty types for which we'll eventually
leave a .DEFERRED_INIT call without a LHS.

2021-09-10  Richard Biener  <rguenther@suse.de>

	PR middle-end/102269
	* gimplify.c (is_var_need_auto_init): Empty types do not need
	initialization.

	* gcc.dg/pr102269.c: New testcase.
---

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 3314f76cf3ff..8820f873993f 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -1826,7 +1826,8 @@ is_var_need_auto_init (tree decl)
 {
   if (auto_var_p (decl)
       && (flag_auto_var_init > AUTO_INIT_UNINITIALIZED)
-      && (!lookup_attribute ("uninitialized", DECL_ATTRIBUTES (decl))))
+      && (!lookup_attribute ("uninitialized", DECL_ATTRIBUTES (decl)))
+      && !is_empty_type (TREE_TYPE (decl)))
     return true;
   return false;
 }
diff --git a/gcc/testsuite/gcc.dg/pr102269.c b/gcc/testsuite/gcc.dg/pr102269.c
new file mode 100644
index 000000000000..9d41b8fd7c7f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr102269.c
@@ -0,0 +1,4 @@
+/* { dg-do compile } */
+/* { dg-options "-ftrivial-auto-var-init=zero" } */
+
+void fn() { int a[0]; }