diff options
| author | Robert Griesemer <gri@golang.org> | 2018-01-16 21:30:46 -0800 |
|---|---|---|
| committer | Robert Griesemer <gri@golang.org> | 2018-01-17 18:59:44 +0000 |
| commit | 18d527b3f09521a21e4068917f9b4513fcfcc2ef (patch) | |
| tree | 27a3202bad3dc494375b17ccb1fed215aae91371 /doc/go_spec.html | |
| parent | 2dc025e4e171ee99d31d11efe5ccf53794e89020 (diff) | |
| download | go-18d527b3f09521a21e4068917f9b4513fcfcc2ef.tar.gz go-18d527b3f09521a21e4068917f9b4513fcfcc2ef.zip | |
spec: mention that special case for integer division is due to overflow
Fixes #23443.
Change-Id: If60c39b582ee5308e9fa902f93c1b6ae7890346c
Reviewed-on: https://go-review.googlesource.com/87975
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Diffstat (limited to 'doc/go_spec.html')
| -rw-r--r-- | doc/go_spec.html | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/doc/go_spec.html b/doc/go_spec.html index f009ec0054..1ada626bf0 100644 --- a/doc/go_spec.html +++ b/doc/go_spec.html @@ -1,6 +1,6 @@ <!--{ "Title": "The Go Programming Language Specification", - "Subtitle": "Version of January 11, 2018", + "Subtitle": "Version of January 17, 2018", "Path": "/ref/spec" }--> @@ -3558,9 +3558,10 @@ with <code>x / y</code> truncated towards zero </pre> <p> -As an exception to this rule, if the dividend <code>x</code> is the most -negative value for the int type of <code>x</code>, the quotient -<code>q = x / -1</code> is equal to <code>x</code> (and <code>r = 0</code>). +The one exception to this rule is that if the dividend <code>x</code> is +the most negative value for the int type of <code>x</code>, the quotient +<code>q = x / -1</code> is equal to <code>x</code> (and <code>r = 0</code>) +due to two's-complement <a href="#Integer_overflow">integer overflow</a>: </p> <pre> @@ -3623,11 +3624,11 @@ discard high bits upon overflow, and programs may rely on "wrap around". </p> <p> For signed integers, the operations <code>+</code>, -<code>-</code>, <code>*</code>, and <code><<</code> may legally +<code>-</code>, <code>*</code>, <code>/</code>, and <code><<</code> may legally overflow and the resulting value exists and is deterministically defined by the signed integer representation, the operation, and its operands. -No exception is raised as a result of overflow. A -compiler may not optimize code under the assumption that overflow does +No exception is raised as a result of overflow. +A compiler may not optimize code under the assumption that overflow does not occur. For instance, it may not assume that <code>x < x + 1</code> is always true. </p> |