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Type: Bug
Resolution: Fixed
Priority: P3
Fix Version/s: hs11
Affects Version/s: 7
Component/s: hotspot
Labels:
- performance

Subcomponent:
compiler
Resolved In Build:
b03
CPU:

generic
OS:

generic
Verification:
Verified

Issue	Fix Version	Assignee	Priority	Status	Resolution	Resolved In Build
JDK-2176981	7	Erik Trimble	P3	Closed	Fixed	b17
JDK-2172450	6u10	Abhijit Saha	P3	Resolved	Fixed	b09

The function PhaseCFG::Estimate_Block_Frequency computes blocks frequencies based on IfNode (and other) probabilities. Currenntly, the function stops after two passes, and allows inconsistencies in loops of nesting depths of greater than one, among other places.

Both GCM and Block:is_uncommon() rely on the relative frequencies of blocks in order to make cost/benefit choices in their respective optimizations.

This bug calls for consistency in the estimated frequencies, such that the relative frequencies between two blocks be sane, e.g., frequencies inside a loop be greater than that of the loop head.

backported by

JDK-2172450 Compute consistent block frequencies

Resolved

JDK-2176981 Compute consistent block frequencies

Closed

relates to

JDK-6582890 assert(cost >= 0,"negative spill cost")

Closed

JDK-6586272 uncommon basic blocks not moved to end

Closed

JDK-6843752 missing code for an anti-dependent Phi in GCM

Closed

JDK-8353041 NeverBranchNode causes incorrect block frequency calculation

Resolved

JDK-8346888 [ubsan] block.cpp:1617:30: runtime error: 9.97582e+36 is outside the range of representable values of type 'int'

Resolved

JDK-6584342 assert(hd->head()->is_Loop(),"must begin with loop head node")

Closed

(3 relates to)

Assignee:: Chuck Rasbold

Reporter:: Chuck Rasbold

Votes:: 0 Vote for this issue

Watchers:: 0 Start watching this issue

Created:: 2007-01-08 10:48

Updated:: 2025-03-27 15:43

Resolved:: 2011-03-07 19:25

Imported:: 17/Sep/12 12:26 AM

Indexed:: 19/Jul/12 5:54 PM

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