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| author | Jason Merrill <jason@redhat.com> | 2019-05-22 17:39:08 -0400 |
|---|---|---|
| committer | Jason Merrill <jason@gcc.gnu.org> | 2019-05-22 17:39:08 -0400 |
| commit | c652ff83124334837dc16626f9e1040e4fe41fc9 (patch) | |
| tree | da16d1ea2a867756a78e819cf1274de329d6c07b | |
| parent | 52ea1caf28cdcdff8c9b2be844e3f1be6c369f16 (diff) | |
| download | gcc-c652ff83124334837dc16626f9e1040e4fe41fc9.zip gcc-c652ff83124334837dc16626f9e1040e4fe41fc9.tar.gz gcc-c652ff83124334837dc16626f9e1040e4fe41fc9.tar.bz2 | |
PR c++/20408 - unnecessary code for empty struct.
Here initializing the argument from a TARGET_EXPR isn't an empty class
copy even though the type is !TREE_ADDRESSABLE, so we should check
simple_empty_class_p.
* call.c (build_call_a): Use simple_empty_class_p.
From-SVN: r271523
| -rw-r--r-- | gcc/cp/ChangeLog | 3 | ||||
| -rw-r--r-- | gcc/cp/call.c | 2 | ||||
| -rw-r--r-- | gcc/cp/cp-gimplify.c | 2 | ||||
| -rw-r--r-- | gcc/cp/cp-tree.h | 1 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/tree-ssa/empty-3.C | 16 |
5 files changed, 22 insertions, 2 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 6c98696..88baf86 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,5 +1,8 @@ 2019-05-22 Jason Merrill <jason@redhat.com> + PR c++/20408 - unnecessary code for empty struct. + * call.c (build_call_a): Use simple_empty_class_p. + PR c++/86485 - -Wmaybe-unused with empty class ?: * cp-gimplify.c (simple_empty_class_p): Also true for MODIFY_EXPR. diff --git a/gcc/cp/call.c b/gcc/cp/call.c index 1e16785..4d9331f 100644 --- a/gcc/cp/call.c +++ b/gcc/cp/call.c @@ -393,7 +393,7 @@ build_call_a (tree function, int n, tree *argarray) { tree arg = CALL_EXPR_ARG (function, i); if (is_empty_class (TREE_TYPE (arg)) - && ! TREE_ADDRESSABLE (TREE_TYPE (arg))) + && simple_empty_class_p (TREE_TYPE (arg), arg, INIT_EXPR)) { tree t = build0 (EMPTY_CLASS_EXPR, TREE_TYPE (arg)); arg = build2 (COMPOUND_EXPR, TREE_TYPE (t), arg, t); diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c index 30937b1..7b9607d 100644 --- a/gcc/cp/cp-gimplify.c +++ b/gcc/cp/cp-gimplify.c @@ -593,7 +593,7 @@ gimplify_must_not_throw_expr (tree *expr_p, gimple_seq *pre_p) non-empty CONSTRUCTORs get reduced properly, and we leave the return slot optimization alone because it isn't a copy. */ -static bool +bool simple_empty_class_p (tree type, tree op, tree_code code) { if (TREE_CODE (op) == COMPOUND_EXPR) diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 45a6a70..7ad3c6b 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -7581,6 +7581,7 @@ extern tree cp_fully_fold_init (tree); extern void clear_fold_cache (void); extern tree lookup_hotness_attribute (tree); extern tree process_stmt_hotness_attribute (tree, location_t); +extern bool simple_empty_class_p (tree, tree, tree_code); /* in name-lookup.c */ extern tree strip_using_decl (tree); diff --git a/gcc/testsuite/g++.dg/tree-ssa/empty-3.C b/gcc/testsuite/g++.dg/tree-ssa/empty-3.C new file mode 100644 index 0000000..f340bd4 --- /dev/null +++ b/gcc/testsuite/g++.dg/tree-ssa/empty-3.C @@ -0,0 +1,16 @@ +// PR c++/20408 +// { dg-additional-options -fdump-tree-gimple } +// { dg-final { scan-tree-dump-times "struct Foo" 2 "gimple" } } + +struct Foo {}; +void foo(const Foo&); +void bar(Foo); + +void fooc(void) +{ + foo(Foo()); +} +void barc(void) +{ + bar(Foo()); +} |