From 8ce475543d784f8ce0f7e80f7faff39fa8eb92da Mon Sep 17 00:00:00 2001 From: Jason Merrill 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 **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