Chandler Carruth 424b2b0093 [vectorizer] Teach the loop vectorizer's unroller to only unroll by
powers of two. This is essentially always the correct thing given the
impact on alignment, scaling factors that can be used in addressing
modes, etc. Also, fix the management of the unroll vs. small loop cost
to more accurately model things with this world.

Enhance a test case to actually exercise more of the unroll machinery if
using synthetic constants rather than a specific target model. Before
this change, with the added flags this test will unroll 3 times instead
of either 2 or 4 (the two sensible answers).

While I don't expect this to make a huge difference, if there are lots
of loops sitting right on the edge of hitting the 'small unroll' factor,
they might change behavior. However, I've benchmarked moving the small
loop cost up and down in many various ways and by a huge factor (2x)
without seeing more than 0.2% code size growth. Small adjustments such
as the series that led up here have led to about 1% improvement on some
benchmarks, but it is very close to the noise floor so I mostly checked
that nothing regressed. Let me know if you see bad behavior on other
targets but I don't expect this to be a sufficiently dramatic change to
trigger anything.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200213 91177308-0d34-0410-b5e6-96231b3b80d8
2014-01-27 11:12:24 +00:00
2013-12-04 09:42:49 +00:00
2013-12-20 00:33:39 +00:00
2014-01-17 00:40:39 +00:00

Low Level Virtual Machine (LLVM)
================================

This directory and its subdirectories contain source code for the Low Level
Virtual Machine, a toolkit for the construction of highly optimized compilers,
optimizers, and runtime environments.

LLVM is open source software. You may freely distribute it under the terms of
the license agreement found in LICENSE.txt.

Please see the documentation provided in docs/ for further
assistance with LLVM, and in particular docs/GettingStarted.rst for getting
started with LLVM and docs/README.txt for an overview of LLVM's
documentation setup.

If you're writing a package for LLVM, see docs/Packaging.rst for our
suggestions.

Description
Old fork of llvm-mirror, used on older RPCS3 builds
Readme 850 MiB
Languages
LLVM 52.9%
C++ 32.7%
Assembly 13.2%
Python 0.4%
C 0.4%
Other 0.3%