f1106ef6c9
We try to fold constant computeKnownBits() with context for return instructions only. Otherwise, we rely on SimplifyDemandedBits() to fold instructions with constant known bits. The presence of this special fold for returns is dangerous, because it makes our tests lie about what works and what doesn't. Tests are usually written by returning the result we're interested in, but will go through this separate code path that is not used for anything else. This patch removes the special fold. This primarily regresses patterns of the style "assume(x); return x". The responsibility of handling such patterns lies with passes like EarlyCSE/GVN anyway, which will do this reliably, and not just for returns. Differential Revision: https://reviews.llvm.org/D151099
The LLVM Compiler Infrastructure
Welcome to the LLVM project!
This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.
The LLVM project has multiple components. The core of the project is itself called "LLVM". This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.
C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.
Other components include: the libc++ C++ standard library, the LLD linker, and more.
Getting the Source Code and Building LLVM
Consult the Getting Started with LLVM page for information on building and running LLVM.
For information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.
Getting in touch
Join the LLVM Discourse forums, Discord chat, or #llvm IRC channel on OFTC.
The LLVM project has adopted a code of conduct for participants to all modes of communication within the project.