The following fixes the ICE part of PR78383. We ICE when trying to
turn a computed goto to a CFG edge when we know the label but that
label is in another function (IPA propagation exposed this knowledge).
The transform shows that we miss a DECL_NONLOCAL on the label because
we happily miscompile the testcase by moving the label freely before
the call to the lambda. This results in
_ZZ4mainENKUlPvE_clES_.isra.0.constprop.1:
main:
call _ZZ4mainENKUlPvE_clES_.isra.0.constprop.1
where you can see the goto has been optimized somehow on RTL as well.
Final GIMPLE is
main()::<lambda(void*)> ()
{
<bb 2>:
goto &label;
}
int main() ()
{
label:
main()::<lambda(void*)>::_ZZ4mainENKUlPvE_clES_.isra.0.constprop ();
}
and initial RTL is already broken:
;; goto &label;
(insn 5 4 6 (set (reg:DI 87)
(label_ref/v:DI 0)) "t.ii":3 -1
(nil))
(jump_insn 6 5 7 (set (pc)
(reg:DI 87)) "t.ii":3 -1
(nil))
looks like it might be a bad idea to freely allow LABEL_DECL address
propagation but in the end it works fine for DECL_NONLOCAL labels
so I think this is what we miss (the label is not marked DECL_NONLOCAL).
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
Will commit w/o the testcase (because that is still miscompiled).
Richard.
2016-11-17 Richard Biener <rguent...@suse.de>
PR middle-end/78383
* tree-cfgcleanup.c (cleanup_control_flow_bb): Do not turn
non-local goto into CFG.
diff --git a/gcc/testsuite/g++.dg/torture/pr78383.C
b/gcc/testsuite/g++.dg/torture/pr78383.C
new file mode 100644
index 0000000..2b35bc7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr78383.C
@@ -0,0 +1,11 @@
+// { dg-do run }
+
+int main()
+{
+ auto f = [](void* ptr) { goto *ptr; };
+
+ f(&&label);
+
+label:
+ return 0;
+}
diff --git a/gcc/tree-cfgcleanup.c b/gcc/tree-cfgcleanup.c
index 21873f8..fe22ed3 100644
--- a/gcc/tree-cfgcleanup.c
+++ b/gcc/tree-cfgcleanup.c
@@ -230,6 +230,8 @@ cleanup_control_flow_bb (basic_block bb, bool first_p)
edges which do not go to the right block. For the one
edge which goes to the right block, fix up its flags. */
label = TREE_OPERAND (gimple_goto_dest (stmt), 0);
+ if (DECL_CONTEXT (label) != cfun->decl)
+ return retval;
target_block = label_to_block (label);
for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
{
