RFR: 8344026: Ubsan: prevent potential integer overflow in c1_LIRGenerator_<arch>.cpp file [v8]

[Emanuel Peter]

On Wed, 4 Dec 2024 10:10:06 GMT, Andrew Haley <aph at openjdk.org> wrote:

>>>And do you have some sort of tests for this, to make sure we check with all possible c values?
>> 
>> No, as of now I only ran tier1 test cases with c1 compiler. Nothing else.
>
> All that `java_add` does is cast to unsigned and then add. That's equivalent to what we're doing here, but explicit casts make the arithmetic clearer, IMO.

Ok, I forgot that unsigned has properly defined overflow semantics.

> No, as of now I only ran tier1 test cases with c1 compiler. Nothing else.

Tests would really be great. Is that possible?

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PR Review Comment: https://git.openjdk.org/jdk/pull/22144#discussion_r1869132100