hanchenye-llvm-project/clang
Craig Topper 9d8e9ff620 [X86] Enable isel to use the PAUSE instruction even when SSE2 is disabled. Clang part
Summary:
On older processors this instruction encoding is treated as a NOP.

MSVC doesn't disable intrinsics based on features the way clang/gcc does. Because the PAUSE instruction encoding doesn't crash older processors, some software out there uses these intrinsics without checking for SSE2.

This change also seems to also be consistent with gcc behavior.

Fixes PR34079

Reviewers: RKSimon, zvi

Reviewed By: RKSimon

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D36362

llvm-svn: 310191
2017-08-05 23:35:54 +00:00
..
INPUTS
bindings [libclang] Support for querying whether an enum is scoped 2017-07-12 11:35:11 +00:00
cmake Enable AddressSanitizer for Fuchsia targets 2017-08-03 23:02:22 +00:00
docs Add OpenCL 2.0 atomic builtin functions as Clang builtin 2017-08-04 18:16:31 +00:00
examples
include [X86] Enable isel to use the PAUSE instruction even when SSE2 is disabled. Clang part 2017-08-05 23:35:54 +00:00
lib [OpenCL] Remove extra select functions from opencl-c.h 2017-08-05 02:23:47 +00:00
runtime
test [X86] Enable isel to use the PAUSE instruction even when SSE2 is disabled. Clang part 2017-08-05 23:35:54 +00:00
tools [libclang] Determinize order of platform availability attrs 2017-08-04 21:52:25 +00:00
unittests [ASTMatcher] Add handling for DeducedType to HasDeclarationMatcher 2017-08-04 18:59:19 +00:00
utils [Bash-autocompletion] Show HelpText with possible flags 2017-07-26 13:36:58 +00:00
www [Analyzer] Add support for displaying cross-file diagnostic paths in HTML output 2017-08-03 18:12:22 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt [CMake] NFC. Add clang-tablegen-targets utility target 2017-07-28 15:33:47 +00:00
CODE_OWNERS.TXT
INSTALL.txt
LICENSE.TXT
ModuleInfo.txt
NOTES.txt
README.txt Remove test commit. 2017-06-30 03:03:28 +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/