RFR: 8281518: New optimization: convert "(x|y)-(x^y)" into "x&y" [v2]

[Quan Anh Mai]

On Wed, 9 Feb 2022 16:04:48 GMT, Zhiqiang Zang <duke at openjdk.java.net> wrote:

>> Convert `(x|y)-(x^y)` into `x&y`, in `SubINode::Ideal` and `SubLNode::Ideal`.
>> 
>> The results of the microbenchmark are as follows:
>> 
>> Baseline:                                                                                                                                         
>> Benchmark                                Mode  Cnt  Score   Error  Units
>> SubIdeal_XOrY_Minus_XXorY_.baselineInt   avgt   60  0.481 ± 0.003  ns/op
>> SubIdeal_XOrY_Minus_XXorY_.baselineLong  avgt   60  0.482 ± 0.004  ns/op
>> SubIdeal_XOrY_Minus_XXorY_.testInt       avgt   60  0.901 ± 0.007  ns/op
>> SubIdeal_XOrY_Minus_XXorY_.testLong      avgt   60  0.894 ± 0.004  ns/op
>> 
>> Patch:
>> Benchmark                                Mode  Cnt  Score   Error  Units
>> SubIdeal_XOrY_Minus_XXorY_.baselineInt   avgt   60  0.480 ± 0.003  ns/op
>> SubIdeal_XOrY_Minus_XXorY_.baselineLong  avgt   60  0.483 ± 0.005  ns/op
>> SubIdeal_XOrY_Minus_XXorY_.testInt       avgt   60  0.600 ± 0.004  ns/op
>> SubIdeal_XOrY_Minus_XXorY_.testLong      avgt   60  0.602 ± 0.004  ns/op
>
> Zhiqiang Zang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   include bug id.

Hi,

For clarification, my idea is to look at GCC and clang's codebases to see if there is a more general way to achieve every transformation elegantly instead of naively matching every combination, which may mitigate the cost for each additional transformation.

Thanks.

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PR: https://git.openjdk.java.net/jdk/pull/7395