RFR: 8283726: x86_64 intrinsics for compareUnsigned method in Integer and Long

Tue Jun 7 18:14:19 UTC 2022

On Tue, 7 Jun 2022 17:14:18 GMT, Quan Anh Mai <duke at openjdk.java.net> wrote:

> Hi,
> 
> This patch implements intrinsics for `Integer/Long::compareUnsigned` using the same approach as the JVM does for long and floating-point comparisons. This allows efficient and reliable usage of unsigned comparison in Java, which is a basic operation and is important for range checks such as discussed in #8620 .
> 
> Thank you very much.

Please add microbenchmark and show its results.

src/hotspot/share/opto/subnode.hpp line 217:

> 215: //------------------------------CmpU3Node--------------------------------------
> 216: // Compare 2 unsigned values, returning integer value (-1, 0 or 1).
> 217: class CmpU3Node : public CmpUNode {

Place it after `CmpUNode` class.

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PR: https://git.openjdk.java.net/jdk/pull/9068