[Bug target/87047] [7/8/9 Regression] performance regression because of if-conversion

[amonakov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87047

--- Comment #5 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
... and avoiding the wrong branch fixes this bug without regressing pr78120.c
testcase:

--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -3413,7 +3413,7 @@ noce_process_if_block (struct noce_if_info *if_info)
                                       &if_info->else_simple))
     return false;

-  if (else_bb == NULL)
+  if (0 && else_bb == NULL)
     if_info->original_cost += then_cost;
   else if (speed_p)
     if_info->original_cost += MIN (then_cost, else_cost);