diff mbox series

Fix profile update in tree-ssa-loop-im.cc

Message ID ZMJ9PZiYSPTP8YP0@kam.mff.cuni.cz
State New
Headers show
Series Fix profile update in tree-ssa-loop-im.cc | expand

Commit Message

Jan Hubicka July 27, 2023, 2:20 p.m. UTC 
Hi,
this fixes two bugs in tree-ssa-loop-im.cc.  First is that cap probability is not
reliable, but it is constructed with adjusted quality.  Second is that sometimes
the conditional has wrong joiner BB count.  This is visible on
testsuite/gcc.dg/pr102385.c however the testcase triggers another profile
update bug in pcom, so I will update it in followup patch.

gcc/ChangeLog:

	* tree-ssa-loop-im.cc (execute_sm_if_changed): Turn cap probability
	to guessed; fix count of new_bb.
diff mbox series

Patch

diff --git a/gcc/tree-ssa-loop-im.cc b/gcc/tree-ssa-loop-im.cc
index f5b01e986ae..268f466bdc9 100644
--- a/gcc/tree-ssa-loop-im.cc
+++ b/gcc/tree-ssa-loop-im.cc
@@ -2059,7 +2059,8 @@  execute_sm_if_changed (edge ex, tree mem, tree tmp_var, tree flag,
        nbbs++;
     }
 
-  profile_probability cap = profile_probability::always ().apply_scale (2, 3);
+  profile_probability cap
+	  = profile_probability::guessed_always ().apply_scale (2, 3);
 
   if (flag_probability.initialized_p ())
     ;
@@ -2103,6 +2104,8 @@  execute_sm_if_changed (edge ex, tree mem, tree tmp_var, tree flag,
 
   old_dest = ex->dest;
   new_bb = split_edge (ex);
+  if (append_cond_position)
+    new_bb->count += last_cond_fallthru->count ();
   then_bb = create_empty_bb (new_bb);
   then_bb->count = new_bb->count.apply_probability (flag_probability);
   if (irr)