[Bug tree-optimization/67915] ICE on valid code at -O2 and -O3 on x86_64-linux-gnu

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67915

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
So sth like the following (ISTR some missed foldings that way, it's not too
long
ago that I tested this)

Index: gcc/tree-cfgcleanup.c
===================================================================
--- gcc/tree-cfgcleanup.c       (revision 228706)
+++ gcc/tree-cfgcleanup.c       (working copy)
@@ -110,10 +110,9 @@ cleanup_control_expr_graph (basic_block
       switch (gimple_code (stmt))
        {
        case GIMPLE_COND:
-         val = fold_binary_loc (loc, gimple_cond_code (stmt),
-                                boolean_type_node,
-                                gimple_cond_lhs (stmt),
-                                gimple_cond_rhs (stmt));
+         val = const_binop (gimple_cond_code (stmt),
+                            boolean_type_node,
+                            gimple_cond_lhs (stmt), gimple_cond_rhs (stmt));
          break;

        case GIMPLE_SWITCH:

Or alternatively try to go down

Index: gcc/passes.c
===================================================================
--- gcc/passes.c        (revision 228750)
+++ gcc/passes.c        (working copy)
@@ -1909,7 +1909,16 @@ execute_function_todo (function *fn, voi

   push_cfun (fn);

-  /* Always cleanup the CFG before trying to update SSA.  */
+  if (flags & TODO_update_ssa_any)
+    {
+      /* Always delete unreachable blocks before trying to update SSA.  */
+      if (!dom_info_available_p (CDI_DOMINATORS))
+       delete_unreachable_blocks ();
+
+      unsigned update_flags = flags & TODO_update_ssa_any;
+      update_ssa (update_flags);
+    }
+
   if (flags & TODO_cleanup_cfg)
     {
       cleanup_tree_cfg ();
@@ -1930,10 +1939,9 @@ execute_function_todo (function *fn, voi
         still need to do one.  */
       if (!(flags & TODO_update_ssa_any) && need_ssa_update_p (cfun))
        flags |= TODO_update_ssa;
-    }

-  if (flags & TODO_update_ssa_any)
-    {
+      /* ???  We want to fix the above issue by keeping SSA for up-to-date
+         which might be easier when we have updated SSA before CFG cleanup. 
*/
       unsigned update_flags = flags & TODO_update_ssa_any;
       update_ssa (update_flags);
     }

with all the consequences of even after fixing ??? the probably more expensive
SSA update (on a not cleaned up CFG).

I'm re-testing the first hunk (without instrumenting for regressions...)