RFR: 8347645: C2: XOR bounded value handling blocks constant folding [v7]
Johannes Graham
duke at openjdk.org
Sat Jan 25 16:23:00 UTC 2025
> C2 does not eliminate XOR nodes with constant arguments. This has a noticeable effect on `Long.expand` with a constant mask, on architectures that don't have instructions equivalent to `PDEP` to be used in an intrinsic.
>
> This patch demonstrates a potential fix to the problem, but there might well be better ways to do it.
Johannes Graham has updated the pull request incrementally with three additional commits since the last revision:
- formatting
- simplified version of bounds check
- tests for xor hi=power of 2
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/23089/files
- new: https://git.openjdk.org/jdk/pull/23089/files/4d4eeb15..cafdbfd7
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=23089&range=06
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=23089&range=05-06
Stats: 131 lines in 3 files changed: 108 ins; 3 del; 20 mod
Patch: https://git.openjdk.org/jdk/pull/23089.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/23089/head:pull/23089
PR: https://git.openjdk.org/jdk/pull/23089
More information about the hotspot-compiler-dev
mailing list