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Type: Enhancement
Resolution: Fixed
Priority: P5
Fix Version/s: hs16
Affects Version/s: hs15
Component/s: hotspot
Labels:
- performance
- verify-pit

Subcomponent:
compiler
Resolved In Build:
b04
CPU:

generic
OS:

generic
Verification:
Verified

Issue	Fix Version	Assignee	Priority	Status	Resolution	Resolved In Build
JDK-2179100	7	Christian Thalinger	P5	Closed	Fixed	b61
JDK-2180639	6u18	Christian Thalinger	P5	Closed	Fixed	b01

These methods can be instrinsified by using bit scan, bit test, and population count instructions. It seems it's not worth to instrinsify lowestOneBit() too, as it already boilds down to about 2 or 3 machine instructions.

Some of these methods can be used in BigInteger and maybe other classes in the JDK.
I removed highestOneBit from that CR as it's not clear the benefit is worth the changes. I might open another one in the future.

backported by

JDK-2179100 Add intrinsics for {Integer,Long}.{numberOfLeadingZeros,numberOfTrailingZeros}()

Closed

JDK-2180639 Add intrinsics for {Integer,Long}.{numberOfLeadingZeros,numberOfTrailingZeros}()

Closed

relates to

JDK-7100757 The BitSet.nextSetBit() produces incorrect result in 32bit VM on Sparc

Resolved

JDK-6832035 BigInteger and MutableBigInteger should use Integer bit-twiddling methods

Closed

JDK-6996240 The BitSet.length method sometimes returns an index+1 value less than that of the highest bit set.

Closed

JDK-8035857 Add tests to verify correctness of operations with BMI1 and LZCNT instructions

Resolved

(1 relates to)

Assignee:: Christian Thalinger (Inactive)

Reporter:: Christian Thalinger (Inactive)

Votes:: 0 Vote for this issue

Watchers:: 0 Start watching this issue

Created:: 2009-03-27 16:02

Updated:: 2014-02-27 09:34

Resolved:: 2011-03-07 21:03

Imported:: 17/Sep/12 12:47 AM

Indexed:: 19/Jul/12 6:05 PM

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