From: Jan Hubicka <jh@suse.cz>
Date: Thu, 27 Jul 2023 13:57:54 +0000 (+0200)
Subject: Fix profile_count::apply_probability
X-Git-Tag: basepoints/gcc-15~7317
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=499b8079a6419bb8082de062ec30772296c6700c;p=thirdparty%2Fgcc.git

Fix profile_count::apply_probability

profile_count::apply_probability misses check for uninitialized probability which leads
to completely random results on applying uninitialized probability to initialized scale.
This can make difference when i.e. inlining -fno-guess-branch-probability function
to -fguess-branch-probability one.

gcc/ChangeLog:

	* profile-count.h (profile_count::apply_probability): Fix
	handling of uninitialized probabilities, optimize scaling
	by probability 1.
---

diff --git a/gcc/profile-count.h b/gcc/profile-count.h
index bf1136782a3b..88a6431c21a0 100644
--- a/gcc/profile-count.h
+++ b/gcc/profile-count.h
@@ -1129,11 +1129,11 @@ public:
   /* Scale counter according to PROB.  */
   profile_count apply_probability (profile_probability prob) const
     {
-      if (*this == zero ())
+      if (*this == zero () || prob == profile_probability::always ())
 	return *this;
       if (prob == profile_probability::never ())
 	return zero ();
-      if (!initialized_p ())
+      if (!initialized_p () || !prob.initialized_p ())
 	return uninitialized ();
       profile_count ret;
       uint64_t tmp;