llvm-project/clang
Craig Topper 635d383fad [X86] Enable -mprefer-vector-width=256 by default for Skylake-avx512 and later Intel CPUs.
AVX512 instructions can cause a frequency drop on these CPUs. This
can negate the performance gains from using wider vectors. Enabling
prefer-vector-width=256 will prevent generation of zmm registers
unless explicit 512 bit operations are used in the original source
code.

I believe gcc and icc both do something similar to this by default.

Differential Revision: https://reviews.llvm.org/D67259

llvm-svn: 371694
2019-09-11 23:54:36 +00:00
..
INPUTS
bindings [clang][Tooling] Infer target and mode from argv[0] when using JSONCompilationDatabase 2019-06-26 07:39:03 +00:00
cmake [CMake][Fuchsia] Enable experimental pass manager by default 2019-08-29 23:12:06 +00:00
docs [X86] Enable -mprefer-vector-width=256 by default for Skylake-avx512 and later Intel CPUs. 2019-09-11 23:54:36 +00:00
examples Fixup build of clang-interpreter example after change in r370122. 2019-08-28 02:13:24 +00:00
include [analyzer] NFC: Move PathDiagnostic classes to libAnalysis. 2019-09-11 20:54:27 +00:00
lib [clang-scan-deps] cast Result to ErrorOr<unique_ptr<vfs::File>> explicitly to avoid s390x-linux buildbot failure 2019-09-11 21:00:13 +00:00
runtime [GWP-ASan] Mutex implementation [2]. 2019-05-30 19:45:32 +00:00
test Fix up a test updated in r371655 - require case-insensitive file system. 2019-09-11 21:19:27 +00:00
tools [clang-scan-deps] add skip excluded conditional preprocessor block preprocessing optimization 2019-09-11 20:40:31 +00:00
unittests [clang-scan-deps] add skip excluded conditional preprocessor block preprocessing optimization 2019-09-11 20:40:31 +00:00
utils [OpenCL] Add image type handling for builtins 2019-09-05 10:01:24 +00:00
www [c++20] P1143R2: Add support for the C++20 'constinit' keyword. 2019-09-04 20:30:37 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt [CMake] Don't set Python_ADDITIONAL_VERSIONS 2019-07-18 15:17:42 +00:00
CODE_OWNERS.TXT
INSTALL.txt
LICENSE.TXT
ModuleInfo.txt
NOTES.txt
README.txt [NFC] Test commit 2019-06-12 07:50:48 +00:00

README.txt

//===----------------------------------------------------------------------===//
// C Language Family Front-end
//===----------------------------------------------------------------------===//

Welcome to Clang.  This is a compiler front-end for the C family of languages
(C, C++, Objective-C, and Objective-C++) which is built as part of the LLVM
compiler infrastructure project.

Unlike many other compiler frontends, Clang is useful for a number of things
beyond just compiling code: we intend for Clang to be host to a number of
different source-level tools.  One example of this is the Clang Static Analyzer.

If you're interested in more (including how to build Clang) it is best to read
the relevant web sites.  Here are some pointers:

Information on Clang:             http://clang.llvm.org/
Building and using Clang:         http://clang.llvm.org/get_started.html
Clang Static Analyzer:            http://clang-analyzer.llvm.org/
Information on the LLVM project:  http://llvm.org/

If you have questions or comments about Clang, a great place to discuss them is
on the Clang development mailing list:
  http://lists.llvm.org/mailman/listinfo/cfe-dev

If you find a bug in Clang, please file it in the LLVM bug tracker:
  http://llvm.org/bugs/