diff options
| author | Sanjoy Das <sanjoy@playingwithpointers.com> | 2016-11-13 23:40:40 +0000 |
|---|---|---|
| committer | Sanjoy Das <sanjoy@playingwithpointers.com> | 2016-11-13 23:40:40 +0000 |
| commit | 00eb18da3b9e87bad38aaba31bd299cb8850b845 (patch) | |
| tree | ddb8b52588a364ea1239423a4e8fd36a11230ff3 /docs | |
| parent | 5b20442fc20a0351554dbf2515890110d5c17b01 (diff) | |
[LangRef] Drop misleading anecdote
`shl nsw i8 1, i8 8` is poison, but `mul i8 1, i8 128` is not.
This was discussed previously here:
http://lists.llvm.org/pipermail/llvm-dev/2015-April/084195.html. From
the discussion, it was not clear which semantics we want for `shl`, but
for now at least make the language reference more accurate.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286785 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/LangRef.rst | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/docs/LangRef.rst b/docs/LangRef.rst index f20f4385c2f..c5f927d92ef 100644 --- a/docs/LangRef.rst +++ b/docs/LangRef.rst @@ -6430,9 +6430,7 @@ If the ``nuw`` keyword is present, then the shift produces a :ref:`poison value <poisonvalues>` if it shifts out any non-zero bits. If the ``nsw`` keyword is present, then the shift produces a :ref:`poison value <poisonvalues>` if it shifts out any bits that disagree with the -resultant sign bit. As such, NUW/NSW have the same semantics as they -would if the shift were expressed as a mul instruction with the same -nsw/nuw bits in (mul %op1, (shl 1, %op2)). +resultant sign bit. Example: """""""" |