[lworld] RFR: 8262025: [lworld] C2 should optimize acmp of the same inline type

[Tobias Hartmann]

I've noticed that a simple `val == val` where `val` is an inline type is not optimized by C2. The reason is that we are buffering the inline type operands before applying optimizations. The fix is to simply check for equality before that.

Best regards,
Tobias

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Commit messages:
 - 8262025: [lworld] C2 should optimize acmp of the same inline type

Changes: https://git.openjdk.java.net/valhalla/pull/343/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=343&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8262025
  Stats: 72 lines in 2 files changed: 72 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/343.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/343/head:pull/343

PR: https://git.openjdk.java.net/valhalla/pull/343