[Bug ipa/79787] ICE in remove_unreachable_nodes, at ipa.c:469

[aivchenk at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79787

Alexander Ivchenko <aivchenk at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aivchenk at gmail dot com

--- Comment #2 from Alexander Ivchenko <aivchenk at gmail dot com> ---
Reduced testcase:
inline __attribute__((__always_inline__)) __attribute__ ((target("bmi"))) int
fn1() {}

__attribute__((__always_inline__)) __attribute__ ((target("bmi"))) int fn2() {
fn1(); }

int fn3() { return fn1(); }


Initial call graph:
fn3 -(not inlinable because of attribute mismatch)-> fn1<bmi>
fn2<bmi> -> fn1<bmi>

Call graph before chkp_ecleanup
fn3 -> fn3.chkp -(not inlinable because of attribute mismatch)-> fn1.chkp <bmi>
fn2.chkp <bmi> -> fn1.chkp <bmi>
fn2<bmi> (fn1 is inlined here)


When compiler inlines fn1 to fn2 in expand_call_inline, it removes fn1 cnode,
as it is no longer needed.
There it execute this code (in cgraph_node::remove):

    if (instrumented_version)                                    
      {                                                          
        instrumented_version->instrumented_version = NULL;       
                instrumented_version = NULL;                             
      }
Hence, now fn1.chkp.instrumened_version==NULL and fn1 is removed.

And later on in chkp_cleanup in reachability analysis in
symbol_table::remove_unreachable_nodes 
we fail on this assert, where cnode==fn1.chkp


              /* For instrumentation clones we always need original             
                 function node for proper LTO privatization.  */                
              if (cnode->instrumentation_clone                                  
                  && cnode->definition)                                         
                {                                                               
=>                gcc_assert (cnode->instrumented_version || in_lto_p);

(since fn1 is removed, we don't consider it in chkp_produce_thunks
(early=false))