add some notes
llvm-svn: 145135
diff --git a/llvm/docs/ReleaseNotes.html b/llvm/docs/ReleaseNotes.html
index 68bd0f4..8b533e6 100644
--- a/llvm/docs/ReleaseNotes.html
+++ b/llvm/docs/ReleaseNotes.html
@@ -752,6 +752,9 @@
Better code generation for Cortex-A9
Many APIs take ArrayRef's now.
Pass manager extension API.
+
+
+Information about branch probability and basic block frequency is now available within LLVM based on a combination of static branch prediction heuristics and __builtin_expect calls. That information is currently used for register spill placement and if-conversion, with additional optimizations planned for future releases. The same frameworks are intended for eventual use with profile-guided optimization, but that is not yet implemented.
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