[llvm-branch-commits] [llvm-branch] r295743 - ReleaseNotes: GVNHoist; by Sepastian Pop

[Hans Wennborg via llvm-branch-commits]

Author: hans
Date: Tue Feb 21 12:30:34 2017
New Revision: 295743

URL: http://llvm.org/viewvc/llvm-project?rev=295743&view=rev
Log:
ReleaseNotes: GVNHoist; by Sepastian Pop

Modified:
    llvm/branches/release_40/docs/ReleaseNotes.rst

Modified: llvm/branches/release_40/docs/ReleaseNotes.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_40/docs/ReleaseNotes.rst?rev=295743&r1=295742&r2=295743&view=diff
==============================================================================
--- llvm/branches/release_40/docs/ReleaseNotes.rst (original)
+++ llvm/branches/release_40/docs/ReleaseNotes.rst Tue Feb 21 12:30:34 2017
@@ -61,6 +61,13 @@ Non-comprehensive list of changes in thi
   with LLVM option -adce-remove-loops when the loop body otherwise has
   no live operations.
 
+* The GVNHoist pass is now enabled by default. The new pass based on Global
+  Value Numbering detects similar computations in branch code and replaces
+  multiple instances of the same computation with a unique expression.  The
+  transform benefits code size and generates better schedules.  GVNHoist is
+  more aggressive at -Os and -Oz, hoisting more expressions at the expense of
+  execution time degradations.
+
  * The llvm-cov tool can now export coverage data as json. Its html output mode
    has also improved.