From: Jan Hubicka <jh@suse.cz>
Date: Wed, 28 Nov 2018 20:29:24 +0000 (+0100)
Subject: profile-count.h (profile_count::split): Give better result when splitting profile_pro... 
X-Git-Tag: basepoints/gcc-10~2713
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f0dbeec7c506407aa7e02cc2df82057ea40ab457;p=thirdparty%2Fgcc.git

profile-count.h (profile_count::split): Give better result when splitting profile_probability::always.


	* profile-count.h (profile_count::split): Give better result when
	splitting profile_probability::always.

From-SVN: r266584
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f2e5d828e003..3c1f926e239f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2018-11-28  Jan Hubicka  <jh@suse.cz>
+
+	* profile-count.h (profile_count::split): Give better result when
+	splitting profile_probability::always.
+
 2018-11-28  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR target/88207
diff --git a/gcc/profile-count.h b/gcc/profile-count.h
index 5d3bcc75f6d8..620d6b714579 100644
--- a/gcc/profile-count.h
+++ b/gcc/profile-count.h
@@ -447,8 +447,12 @@ public:
     {
       profile_probability ret = *this * cprob;
       /* The following is equivalent to:
-         *this = cprob.invert () * *this / ret.invert ();  */
-      *this = (*this - ret) / ret.invert ();
+         *this = cprob.invert () * *this / ret.invert ();
+	 Avoid scaling when overall outcome is supposed to be always.
+	 Without knowing that one is inverse of toher, the result would be
+	 conservative.  */
+      if (!(*this == profile_probability::always ()))
+        *this = (*this - ret) / ret.invert ();
       return ret;
     }