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| author | Nikita Popov <npopov@redhat.com> | 2023-10-30 09:04:04 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2023-10-30 09:04:04 +0100 |
| commit | ed3f06b9b393cd51e78e5fbc7a46bce090c1817a (patch) | |
| tree | 54b7960005e583b7cf5c65cbbcc5033a169270a1 /lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp | |
| parent | 41f3b83fb066b4c3273e9abe02a8630864f22f30 (diff) | |
| download | llvm-ed3f06b9b393cd51e78e5fbc7a46bce090c1817a.zip llvm-ed3f06b9b393cd51e78e5fbc7a46bce090c1817a.tar.gz llvm-ed3f06b9b393cd51e78e5fbc7a46bce090c1817a.tar.bz2 | |
[IR] Add zext nneg flag (#67982)
Add an nneg flag to the zext instruction, which specifies that the
argument is non-negative. Otherwise, the result is a poison value.
The primary use-case for the flag is to preserve information when sext
gets replaced with zext due to range-based canonicalization. The nneg
flag allows us to convert the zext back into an sext later. This is
useful for some optimizations (e.g. a signed icmp can fold with sext but
not zext), as well as some targets (e.g. RISCV prefers sext over zext).
Discourse thread: https://discourse.llvm.org/t/rfc-add-zext-nneg-flag/73914
This patch is based on https://reviews.llvm.org/D156444 by
@Panagiotis156, with some implementation simplifications and additional
tests.
---------
Co-authored-by: Panagiotis K <karouzakispan@gmail.com>
Diffstat (limited to 'lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp')
0 files changed, 0 insertions, 0 deletions