Work around JVM miscompile of unsigned integer comparison #1084
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The HotSpot JVM appears to miscompile the intrinsic for unsigned integer comparision in certain compilation tiers. We can avoid it by manually inlining the comparison. Credit to @chirino and @andreaTP for chasing this down with some novel detective work. Fixes dylibso#843
andreaTP
reviewed
Oct 24, 2025
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| public static boolean shouldUseMemWorkaround() { | ||
| return shouldUseMemWorkaround(System.getProperty("java.version")); | ||
| return false; |
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I'm ok with this, should we deprecate this class entirely so that it can be removed in the next major release?
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Surprise! It's failing! Interesting that the fix worked locally though 🤔 |
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It looks like the intrinsic thing was another red herring that affected C2 in an oblique way. So, back to the drawing board! |
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The HotSpot JVM appears to miscompile the intrinsic for unsigned integer comparision in certain compilation tiers. We can avoid it by manually inlining the comparison.
Credit to @chirino and @andreaTP for chasing this down with some novel detective work.
Fixes #843