1 files changed, 54 insertions, 0 deletions
diff --git a/build/unix/build-gcc/PR104142.patch b/build/unix/build-gcc/PR104142.patch
new file mode 100644
index 0000000000..d619510315
--- /dev/null
+++ b/build/unix/build-gcc/PR104142.patch
@@ -0,0 +1,54 @@
+From 8ce475543d784f8ce0f7e80f7faff39fa8eb92da Mon Sep 17 00:00:00 2001
+From: Jason Merrill <jason@redhat.com>
+Date: Mon, 11 Apr 2022 14:50:14 -0400
+Subject: [PATCH] c++: rodata and defaulted ctor [PR104142]
+
+Trivial initialization shouldn't bump a variable out of .rodata; if the
+result of build_aggr_init is an empty STATEMENT_LIST, throw it away.
+
+	PR c++/104142
+
+gcc/cp/ChangeLog:
+
+	* decl.cc (check_initializer): Check TREE_SIDE_EFFECTS.
+
+gcc/testsuite/ChangeLog:
+
+	* g++.dg/opt/const7.C: New test.
+---
+ gcc/cp/decl.c                     | 4 ++++
+ gcc/testsuite/g++.dg/opt/const7.C | 7 +++++++
+ 2 files changed, 11 insertions(+)
+ create mode 100644 gcc/testsuite/g++.dg/opt/const7.C
+
+diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
+index bffbd004167..7b0872cd55e 100644
+--- a/gcc/cp/decl.c
++++ b/gcc/cp/decl.c
+@@ -7227,6 +7227,10 @@ check_initializer (tree decl, tree init, int flags, vec<tree, va_gc> **cleanups)
+   if (init && init != error_mark_node)
+     init_code = build2 (INIT_EXPR, type, decl, init);
+ 
++  if (init_code && !TREE_SIDE_EFFECTS (init_code)
++      && init_code != error_mark_node)
++    init_code = NULL_TREE;
++
+   if (init_code)
+     {
+       /* We might have set these in cp_finish_decl.  */
+diff --git a/gcc/testsuite/g++.dg/opt/const7.C b/gcc/testsuite/g++.dg/opt/const7.C
+new file mode 100644
+index 00000000000..5bcf94897a8
+--- /dev/null
++++ b/gcc/testsuite/g++.dg/opt/const7.C
+@@ -0,0 +1,7 @@
++// PR c++/104142
++// { dg-do compile { target c++11 } }
++// { dg-additional-options -Wunused-variable }
++
++struct B { B()=default; };
++static const B b_var;		//  { dg-bogus "" }
++// { dg-final { scan-assembler-symbol-section {b_var} {^\.(const|rodata)|\[RO\]} } }
+-- 
+2.36.0.1.g2bbe56bd8d
+