[ruby-core:105017] [Ruby master Bug#18078] rb_fix2uint should avoid method lookup and use FIXNUM_NEGATIVE_P

Issue #18078 has been updated by jeremyevans0 (Jeremy Evans).

Status changed from Open to Closed

Fixed by commit:d668cd188ca91cf08ea7678bad1dd0bc8a997a81

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Bug #18078: rb_fix2uint should avoid method lookup and use FIXNUM_NEGATIVE_P
https://bugs.ruby-lang.org/issues/18078#change-93418

* Author: jhawthorn (John Hawthorn)
* Status: Closed
* Priority: Normal
* ruby -v: ruby 3.1.0dev
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
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`rb_fix2uint` checks if the FIXNUM being converted overflows the `unsigned int` type. Previously this check was being done with `rb_num_negative_int_p`, which is equivalent to calling the `<` method on Integer (and checking whether it is overridden), where in this case we are interested in whether the "actual" value can fit inside an `unsigned int`. This also made `rb_fix2uint` potentially behave differently than `rb_num2uint`, which checked the "actual" sign.

This also was slow because `rb_num_negative_int_p` calls `rb_method_basic_definition_p`, doing a method lookup to check for `<` being overridden.

Included is a patch to replace the check in both rb_fix2uint and rb_fix2ushort with FIXNUM_NEGATIVE_P, which simply checks
whether the VALUE is signed. (also submitted as a PR https://github.com/ruby/ruby/pull/4747)

I filed this as a bug, but I don't think this will affect anyone (backport not necessary, nobody should be overriding `Integer#<` I don't think) other than as a performance improvement.

---Files--------------------------------
0001-rb_fix2uint-should-use-FIXNUM_NEGATIVE_P.patch (1.27 KB)


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