llvm-project/clang
Roman Lebedev 03bd5198b6
[OldPM] Pass manager: run SROA after (simple) loop unrolling
I have stumbled into this pretty accidentally, when rewriting
some spaghetti-like code into something more structured,
which involved using some `std::array<>`s. And to my surprise,
the `alloca`s remained, causing about `+160%` perf regression.

https://llvm-compile-time-tracker.com/compare.php?from=bb6f4d32aac3eecb51909f4facc625219307ee68&to=d563e66f40f9d4d145cb2050e41cb961e2b37785&stat=instructions
suggests that this has geomean compile-time cost of `+0.08%`.

Note that D68593 / cecc0d27ad
already did this chage for NewPM, but left OldPM in a pessimized state.

This fixes [[ https://bugs.llvm.org/show_bug.cgi?id=40011 | PR40011 ]], [[ https://bugs.llvm.org/show_bug.cgi?id=42794 | PR42794 ]] and probably some other reports.

Reviewed By: nikic, xbolva00

Differential Revision: https://reviews.llvm.org/D87972
2020-10-04 11:53:50 +03:00
..
INPUTS
bindings [python][tests] Fix string comparison with "is" 2020-09-28 21:11:50 +02:00
cmake [CMake][Fuchsia] Don't set WIN32 API, rely on autodetection 2020-10-01 12:35:52 -07:00
docs [docs] Update ControlFlowIntegrity.rst. 2020-10-02 12:01:05 -07:00
examples [cmake] Fix build of attribute plugin example on Windows 2020-09-07 10:04:32 +02:00
include Revert "[Driver] Move detectLibcxxIncludePath to ToolChain" 2020-10-03 14:22:53 -04:00
lib Revert "[Driver] Move detectLibcxxIncludePath to ToolChain" 2020-10-03 14:22:53 -04:00
runtime [CMake][compiler-rt][libunwind] Compile assembly files as ASM not C, unify workarounds 2020-08-27 15:40:15 +03:00
test [OldPM] Pass manager: run SROA after (simple) loop unrolling 2020-10-04 11:53:50 +03:00
tools [HIP] Align device binary 2020-10-02 18:10:44 -04:00
unittests [Format] Don't treat compound extension headers (foo.proto.h) as foo.cc main-file header. 2020-10-01 19:57:57 +02:00
utils Revert "Recommit "[CUDA][HIP] Defer overloading resolution diagnostics for host device functions"" 2020-09-24 11:16:54 -07:00
www Implements [[likely]] and [[unlikely]] in IfStmt. 2020-09-09 20:48:37 +02:00
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt [cmake] Centralize LLVM_ENABLE_WARNINGS option 2020-09-21 10:23:17 -07:00
CODE_OWNERS.TXT
INSTALL.txt
LICENSE.TXT
ModuleInfo.txt
NOTES.txt
README.txt

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/