Hi!
The local pure const pass notices the static ctor is looping const,
so sets TREE_READONLY and DECL_LOOPING_CONST_OR_PURE_P and does not
clear DECL_STATIC_CONSTRUCTOR bit because it is looping.
Then the ipa pure const pass notices the static ctor is non-looping const,
clears DECL_LOOPING_CONST_OR_PURE_P and DECL_STATIC_CONSTRUCTOR bit,
but because it has been TREE_READONLY already, it doesn't set
TODO_remove_functions from the pass and ipa-comdat pass assumes that
unreachable cgraph nodes have been pruned.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2016-12-12 Jakub Jelinek <ja...@redhat.com>
PR ipa/77905
* ipa-pure-const.c (cdtor_p): Return true for
DECL_STATIC_{CON,DE}STRUCTOR even when it is
DECL_LOOPING_CONST_OR_PURE_P.
* g++.dg/ipa/pr77905.C: New test.
--- gcc/ipa-pure-const.c.jj 2016-09-02 19:09:33.000000000 +0200
+++ gcc/ipa-pure-const.c 2016-12-12 11:51:24.808518093 +0100
@@ -1195,7 +1195,8 @@ static bool
cdtor_p (cgraph_node *n, void *)
{
if (DECL_STATIC_CONSTRUCTOR (n->decl) || DECL_STATIC_DESTRUCTOR (n->decl))
- return !TREE_READONLY (n->decl) && !DECL_PURE_P (n->decl);
+ return ((!TREE_READONLY (n->decl) && !DECL_PURE_P (n->decl))
+ || DECL_LOOPING_CONST_OR_PURE_P (n->decl));
return false;
}
--- gcc/testsuite/g++.dg/ipa/pr77905.C.jj 2016-12-12 11:53:42.645770248
+0100
+++ gcc/testsuite/g++.dg/ipa/pr77905.C 2016-12-12 11:53:35.000000000 +0100
@@ -0,0 +1,21 @@
+// PR ipa/77905
+// { dg-do compile }
+// { dg-options "-O2" }
+
+struct A {
+ A(int);
+};
+struct B : A {
+ B();
+} A;
+struct C : virtual A {
+ C(int);
+};
+A::A(int x) {
+ if (x)
+ A(0);
+}
+
+B::B() : A(1) {}
+
+C::C(int) : A(1) {}
Jakub
