Similar to D123386, this adds D-Movs to the AArch64 perfect shuffle
tables, slightly lowering the costs a little more. This is a rough
improvement in general, especially if you ignore mov v0.16b, v2.16b type
moves that are often artefacts of the calling convention.
The D register movs are encoded as (0x4 | LaneIdx), and to generate a D
register move we are required to bitcast into a higher type, but it is
otherwise very similar to the S-lane mov's already supported.
Differential Revision: https://reviews.llvm.org/D125477
This teaches the perfect shuffle tables about lane inserts, that can
help reduce the cost of many entries. Many of the shuffle masks are
one-away from being correct, and a simple lane move can be a lot simpler
than trying to use ext/zip/etc. Because they are not exactly like the
other masks handled in the perfect shuffle tables, they require special
casing to generate them, with a special InsOp Operator.
The lane to insert into is encoded as the RHSID, and the move from is
grabbed from the original mask. This helps reduce the maximum perfect
shuffle entry cost to 3, with many more shuffles being generatable in a
single instruction.
Differential Revision: https://reviews.llvm.org/D123386
A brief introduction to perfect shuffles - AArch64 NEON has a number of
shuffle operations - dups, zips, exts, movs etc that can in some way
shuffle around the lanes of a vector. Given a shuffle of size 4 with 2
inputs, some shuffle masks can be easily codegen'd to a single
instruction. A <0,0,1,1> mask for example is a zip LHS, LHS. This is
great, but some masks are not so simple, like a <0,0,1,2>. It turns out
we can generate that from zip LHS, <0,2,0,2>, having generated
<0,2,0,2> from uzp LHS, LHS, producing the result in 2 instructions.
It is not obvious from a given mask how to get there though. So we have
a simple program (PerfectShuffle.cpp in the util folder) that can scan
through all combinations of 4-element vectors and generate the perfect
combination of results needed for each shuffle mask (for some definition
of perfect). This is run offline to generate a table that is queried for
generating shuffle instructions. (Because the table could get quite big,
it is limited to 4 element vectors).
In the perfect shuffle tables zip, unz and trn shuffles were being cost
as 2, which is higher than needed and skews the perfect shuffle tables
to create inefficient combinations. This sets them to 1 and regenerates
the tables. The codegen will usually be better and the costs should be
more precise (but it can get less second-order re-use of values from
multiple shuffles, these cases should be fixed up in subsequent patches.
Differential Revision: https://reviews.llvm.org/D123379
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary:
This patch is provided in preparation for removing autoconf on 1/26. The proposal to remove autoconf on 1/26 was discussed on the llvm-dev thread here: http://lists.llvm.org/pipermail/llvm-dev/2016-January/093875.html
"I felt a great disturbance in the [build system], as if millions of [makefiles] suddenly cried out in terror and were suddenly silenced. I fear something [amazing] has happened."
- Obi Wan Kenobi
Reviewers: chandlerc, grosbach, bob.wilson, tstellarAMD, echristo, whitequark
Subscribers: chfast, simoncook, emaste, jholewinski, tberghammer, jfb, danalbert, srhines, arsenm, dschuff, jyknight, dsanders, joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D16471
llvm-svn: 258861
Turn on -Wunused and -Wno-unused-parameter. Clean up most of the resulting
fall out by removing unused variables. Remaining warnings have to do with
unused functions (I didn't want to delete code without review) and unused
variables in generated code. Maintainers should clean up the remaining
issues when they see them. All changes pass DejaGnu tests and Olden.
llvm-svn: 31380
David Green