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 bf1136782a3b4af1a53afa4a17f4cd1a4279ca48..88a6431c21a02c23c9df32a12615837c32f1728e 100644 (file)
--- 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;