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llvm-project/llvm
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guan jian 8d57211d6f
[LLVM][AArch64] Optimize sign bit tests with TST instruction for SIGN_EXTEND patterns (#158061) 
Hi, I recently found out in some cases LLVM doesn't generate optimal
code like:
```
sxtb w8, w0
cmp w8, #0
csel w0, w1, w2, lt
```
```
tst w0, #0x80
csel w0, w1, w2, mi
```

This optimization is only applied when the following conditions are met:
1. The comparison is setlt (signed less than)
2. The right-hand side is zero
3. The left-hand side is a sign extension operation (SIGN_EXTEND or
SIGN_EXTEND_INREG)
4. The sign-extended value has only one use (hasOneUse())
5. The original type is an integer type
2025-09-29 09:53:50 +01:00
..
benchmarks
[llvm] Add benchmarks for Mustache (#160164)
2025-09-25 17:09:05 -07:00
bindings
…
cmake
[LLVM] Remove leftover unnecessary CMake for GPU runtimes
2025-09-20 09:06:48 -05:00
docs
[llvm] Proofread FuzzingLLVM.rst (#161046)
2025-09-28 10:27:36 -07:00
examples
[examples] Fix invalid #ifndef LLVM_*_LINK_INTO_TOOLS (#144340)
2025-09-17 15:56:41 -07:00
include
[llvm][NFC] Simplify alignment calculations in TrailingObjects (#161134)
2025-09-29 00:45:55 -07:00
lib
[LLVM][AArch64] Optimize sign bit tests with TST instruction for SIGN_EXTEND patterns (#158061)
2025-09-29 09:53:50 +01:00
projects
…
resources
…
runtimes
[OpenMP] Allow Fortran tests (#150722)
2025-09-20 13:06:02 +02:00
test
[LLVM][AArch64] Optimize sign bit tests with TST instruction for SIGN_EXTEND patterns (#158061)
2025-09-29 09:53:50 +01:00
tools
[Support] Deprecate one form of support::endian::byte_swap (NFC) (#161045)
2025-09-28 10:27:29 -07:00
unittests
[Support] Deprecate one form of support::endian::byte_swap (NFC) (#161045)
2025-09-28 10:27:29 -07:00
utils
[lit] Remove support for %T
2025-09-26 19:06:09 -07:00
.clang-format
…
.clang-tidy
…
.gitattributes
…
.gitignore
…
CMakeLists.txt
[CAS] LLVM_ENABLE_ONDISK_CAS requires flock on UNIX (#159207)
2025-09-17 16:52:36 +00:00
configure
…
CREDITS.TXT
…
LICENSE.TXT
…
Maintainers.md
[LLVM] Volunteer myself as a secondary maintainer for LoopVectorizer (#120704)
2025-09-23 09:37:47 +01:00
README.txt
…
RELEASE_TESTERS.TXT
…

README.txt 

The LLVM Compiler Infrastructure
================================

This directory and its subdirectories contain source code for LLVM,
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 are writing a package for LLVM, see docs/Packaging.rst for our
suggestions.