[llvm-branch-commits] [llvm-branch] r295743 - ReleaseNotes: GVNHoist; by Sepastian Pop
Hans Wennborg via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Tue Feb 21 10:30:34 PST 2017
Date: Tue Feb 21 12:30:34 2017
New Revision: 295743
ReleaseNotes: GVNHoist; by Sepastian Pop
--- 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.
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