llvm/lib/Transforms/Vectorize
Adam Nemet 367051414e [LoopVectorize] Annotate versioned loop with noalias metadata
Summary:
Use the new LoopVersioning facility (D16712) to add noalias metadata in
the vector loop if we versioned with memchecks.  This can enable some
optimization opportunities further down the pipeline (see the included
test or the benchmark improvement quoted in D16712).

The test also covers the bug I had in the initial version in D16712.

The vectorizer did not previously use LoopVersioning.  The reason is
that the vectorizer performs its transformations in single shot.  It
creates an empty single-block vector loop that it then populates with
the widened, if-converted instructions.  Thus creating an intermediate
versioned scalar loop seems wasteful.

So this patch (rather than bringing in LoopVersioning fully) adds a
special interface to LoopVersioning to allow the vectorizer to add
no-alias annotation while still performing its own versioning.

As the vectorizer propagates metadata from the instructions in the
original loop to the vector instructions we also check the pointer in
the original instruction and see if LoopVersioning can add no-alias
metadata based on the issued memchecks.

Reviewers: hfinkel, nadav, mzolotukhin

Subscribers: mzolotukhin, llvm-commits

Differential Revision: http://reviews.llvm.org/D17191

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263744 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-17 20:32:37 +00:00
..
BBVectorize.cpp ADT: Remove == and != comparisons between ilist iterators and pointers 2016-02-21 20:39:50 +00:00
CMakeLists.txt Use ADDITIONAL_HEADER_DIRS in all LLVM CMake projects. 2015-02-11 03:28:02 +00:00
LLVMBuild.txt Update libdeps since TLI was moved from Target to Analysis in r226078. 2015-01-15 05:21:00 +00:00
LoopVectorize.cpp [LoopVectorize] Annotate versioned loop with noalias metadata 2016-03-17 20:32:37 +00:00
SLPVectorizer.cpp [SLP] Make DataLayout a member variable. 2016-03-16 19:48:42 +00:00
Vectorize.cpp [PM] Remove the old 'PassManager.h' header file at the top level of 2015-02-13 10:01:29 +00:00