[PATCH] [AutoFDO/devirt] Fix ICE with duplicate speculative ID

This happens due to autoprofile pass makes edge make_speculative.
Then ipa-devirt does the same with the same speculative_id which
reults in duplicate speculative_id and ICE.

during IPA pass: cp
test.i:31:1: internal compiler error: verify_cgraph_node failed
0x39bfa6b internal_error(char const*, ...)
	../../gcc/gcc/diagnostic-global-context.cc:787
0x13914eb cgraph_node::verify_node()
	../../gcc/gcc/cgraph.cc:4454
0x13738ab symtab_node::verify()
	../../gcc/gcc/symtab.cc:1377
0x1373d1b symtab_node::verify_symtab_nodes()
	../../gcc/gcc/symtab.cc:1499
0x13a3653 symtab_node::checking_verify_symtab_nodes()
	../../gcc/gcc/cgraph.h:718
0x182d267 symbol_table::remove_unreachable_nodes(_IO_FILE*)
	../../gcc/gcc/ipa.cc:688
0x19f8c33 execute_todo
	../../gcc/gcc/passes.cc:2163

We may also have to check if the speculative edge is present
before making speculative.

gcc/ChangeLog:

2025-12-22  Kugan Vivekanandarajah  <kvivekananda@nvidia.com>

	* cgraph.cc (cgraph_edge::get_next_speculative_id): New.
	* cgraph.h (cgraph_edge::get_next_speculative_id): New.
	* ipa-devirt.cc (ipa_devirt): Use get_next_speculative_id
	in make_speculative.

Signed-off-by: Kugan Vivekanandarajah <kvivekananda@nvidia.com>

diff --git a/gcc/cgraph.cc b/gcc/cgraph.cc
index 9e273642dab99d5fdf7eef20b5d21ee9a49663d8..0c1995dcfbdb720aa4be50bb30201af8ac3a3e79 100644 (file)
--- a/gcc/cgraph.cc
+++ b/gcc/cgraph.cc
@@ -1265,6 +1265,32 @@ cgraph_edge::remove (cgraph_edge *edge)
   symtab->free_edge (edge);
 }
 
+/* Returns the next speculative_id based on currently in use
+   for the given statement for the edge.
+   Returns 0 if no speculative edges exist for this statement. */
+
+int
+cgraph_edge::get_next_speculative_id ()
+{
+  int max_id = -1;
+  cgraph_edge *e;
+
+  /* Iterate through all edges leaving this caller */
+  for (e = caller->callees; e; e = e->next_callee)
+    {
+      /* Match the specific GIMPLE statement and check the
+        speculative flag */
+      if (e->call_stmt == call_stmt && e->speculative)
+       {
+         if (e->speculative_id > max_id)
+           max_id = e->speculative_id;
+       }
+    }
+
+  return max_id + 1;
+}
+
+
 /* Turn edge into speculative call calling N2. Update
    the profile so the direct call is taken COUNT times
    with FREQUENCY.

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index dbbab4087a9a65d81ea1fc64fe642a2466218f72..d471ce85c1ed9d2c3c35aa64e7228a4184b631c1 100644 (file)
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -1894,6 +1894,11 @@ public:
      call.  */
   static cgraph_edge *make_direct (cgraph_edge *edge, cgraph_node *callee);
 
+  /* Returns the next speculative_id based on currently in use
+     for the given statement for the edge.
+     Returns 0 if no speculative edges exist for this statement. */
+  int get_next_speculative_id ();
+
   /* Turn edge into speculative call calling N2. Update
      the profile so the direct call is taken COUNT times
      with FREQUENCY.  speculative_id is used to link direct calls with their

diff --git a/gcc/ipa-devirt.cc b/gcc/ipa-devirt.cc
index bb0f5c7671022bf6182aabc57c5b991c397f4c01..0b7e8bb6fae694e330ee487a11af0f8cbd65c320 100644 (file)
--- a/gcc/ipa-devirt.cc
+++ b/gcc/ipa-devirt.cc
@@ -3865,7 +3865,7 @@ ipa_devirt (void)
                continue;
              }
            bool first = true;
-           unsigned speculative_id = 0;
+           unsigned speculative_id = e->get_next_speculative_id ();
            for (cgraph_node * likely_target: likely_targets)
              {
                if (!devirt_target_ok_p (likely_target, &stats))
@@ -3940,7 +3940,8 @@ ipa_devirt (void)
 
                update = true;
                e->make_speculative (likely_tgt_node,
-                                    e->count.apply_scale (8, 10));
+                                    e->count.apply_scale (8, 10),
+                                    e->get_next_speculative_id ());
              }
          }
       if (update)