Withdrawn: 8305324: C2: Wrong execution of vectorizing Interger.reverseBytes
Daohan Qu
duke at openjdk.org
Mon Apr 10 12:59:52 UTC 2023
On Mon, 10 Apr 2023 10:49:24 GMT, Daohan Qu <duke at openjdk.org> wrote:
> This patch should fix [JDK-8305324](https://bugs.openjdk.org/browse/JDK-8305324).
>
> `SuperWord::compute_vector_element_type()` propagates backward a narrower integer type when the upper bits of the value are not needed. However, `Integer.reverseBytes()` depends on higher order bits of an integer and should be prevented from being vectorized like `Math.abs()`( which is `Op_AbsI` in the following code).
>
> https://github.com/openjdk/jdk/blob/0243da2e4adc1b7ab6fcd5b10778532101158dce/src/hotspot/share/opto/superword.cpp#L3935-L3945
>
> I have tested this patch for tier 1-3 on x86-64.
This pull request has been closed without being integrated.
-------------
PR: https://git.openjdk.org/jdk/pull/13404
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