[Bug tree-optimization/99101] optimization bug with -ffinite-loops

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99101

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
So

@@ -1661,6 +1662,7 @@ perform_tree_ssa_dce (bool aggressive)
   if (aggressive)
     {
       /* Compute control dependence.  */
+      connect_infinite_loops_to_exit ();
       calculate_dominance_info (CDI_POST_DOMINATORS);
       cd = new control_dependences ();


"fixes" it (plus related changes), but

@@ -1661,6 +1662,7 @@ perform_tree_ssa_dce (bool aggressive)
   if (aggressive)
     {
       /* Compute control dependence.  */
+      add_noreturn_fake_exit_edges ();
+      connect_infinite_loops_to_exit ();
       calculate_dominance_info (CDI_POST_DOMINATORS);
       cd = new control_dependences ();


breaks it again.  Similar to perturbing block numbering in a way so that
connect_infinite_loops_to_exit would first visit the noreturn block.