From 499b8079a6419bb8082de062ec30772296c6700c Mon Sep 17 00:00:00 2001
From: Jan Hubicka <jh@suse.cz>
Date: Thu, 27 Jul 2023 15:57:54 +0200
Subject: [PATCH] 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.
---
gcc/profile-count.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
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;
--
GitLab