Hi!
As discussed in the PR, returns_twice functions are rare/special beasts
that need special treatment in the cfg, and inside of their bodies
we don't know which part actually works the weird returns twice way
(either in the fork/vfork sense, or in the setjmp) and aren't updating
ab edges to reflect that.
I think easiest is just to never split these, like we already never
split noreturn or malloc functions.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2023-02-07 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/106923
* ipa-split.cc (execute_split_functions): Don't split returns_twice
functions.
* gcc.dg/pr106923.c: New test.
--- gcc/ipa-split.cc.jj 2023-01-02 09:32:22.492283737 +0100
+++ gcc/ipa-split.cc 2023-02-06 14:15:08.343271251 +0100
@@ -1715,10 +1715,11 @@ execute_split_functions (void)
struct cgraph_node *node = cgraph_node::get (current_function_decl);
if (flags_from_decl_or_type (current_function_decl)
- & (ECF_NORETURN|ECF_MALLOC))
+ & (ECF_NORETURN|ECF_MALLOC|ECF_RETURNS_TWICE))
{
if (dump_file)
- fprintf (dump_file, "Not splitting: noreturn/malloc function.\n");
+ fprintf (dump_file, "Not splitting: noreturn/malloc/returns_twice "
+ "function.\n");
return 0;
}
if (MAIN_NAME_P (DECL_NAME (current_function_decl)))
--- gcc/testsuite/gcc.dg/pr106923.c.jj 2023-02-06 14:19:33.464449400 +0100
+++ gcc/testsuite/gcc.dg/pr106923.c 2023-02-06 14:18:25.498429162 +0100
@@ -0,0 +1,23 @@
+/* PR tree-optimization/106923 */
+/* { dg-do compile } */
+/* { dg-options "-O1 -finline-small-functions -fpartial-inlining --param
max-inline-insns-single=1 --param uninlined-function-insns=10000" } */
+
+int n;
+
+int
+baz (void);
+
+__attribute__ ((returns_twice)) int
+bar (void)
+{
+ if (baz ())
+ ++n;
+
+ return 0;
+}
+
+int
+foo (void)
+{
+ return bar ();
+}
Jakub
