Hi, as requested by Jakub, this patch makes devirtualization code to turn off transformations based on assumption that cxa_pure_virtual will never be called by a virtual call when -fsanitize=undefined is used.
Bootstrapped/regtested x86_64-linux, will commit it shortly. PR ipa/66223 * ipa-devirt.c (maybe_record_node): Do not optimize cxa_pure_virtual calls when sanitizing. (possible_polymorphic_call_target_p)" FIx formating. * g++.dg/ipa/devirt-51.C: New testcase. Index: ipa-devirt.c =================================================================== --- ipa-devirt.c (revision 234715) +++ ipa-devirt.c (working copy) @@ -2438,10 +2438,14 @@ maybe_record_node (vec <cgraph_node *> & { gcc_assert (!target_node->global.inlined_to); gcc_assert (target_node->real_symbol_p ()); + /* When sanitizing, do not asume that cxa_pure_virutal is not called + by valid program. */ + if (flag_sanitize & SANITIZE_UNDEFINED) + ; /* Only add pure virtual if it is the only possible target. This way we will preserve the diagnostics about pure virtual called in many cases without disabling optimization in other. */ - if (pure_virtual) + else if (pure_virtual) { if (nodes.length ()) return; @@ -3374,8 +3378,7 @@ possible_polymorphic_call_target_p (tree bool final; if (TREE_CODE (TREE_TYPE (n->decl)) == FUNCTION_TYPE - && ((fcode = DECL_FUNCTION_CODE (n->decl)) - == BUILT_IN_UNREACHABLE + && ((fcode = DECL_FUNCTION_CODE (n->decl)) == BUILT_IN_UNREACHABLE || fcode == BUILT_IN_TRAP)) return true; Index: testsuite/g++.dg/ipa/devirt-51.C =================================================================== --- testsuite/g++.dg/ipa/devirt-51.C (revision 0) +++ testsuite/g++.dg/ipa/devirt-51.C (working copy) @@ -0,0 +1,29 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fsanitize=undefined -fdump-tree-optimized" } */ +namespace { + struct B { + B* self; + B() : self( this ) { self->f(); } + void E(void); + virtual void f() = 0; + }; + + struct D : B + { + void f() {} + }; +} + +struct D e; + +__attribute__ ((used)) +void B::E(void) + { + this->f(); +} + + int main() + { + D d; + } +/* { dg-final { scan-tree-dump "cxa_pure_virtual" "optimized" } } */