JDK-8151882 : -XX:+Verbose prints messages even if no other flag is set
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 9
  • Priority: P5
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2016-03-15
  • Updated: 2016-04-14
  • Resolved: 2016-03-17
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JDK 9
9 b114Fixed
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Relates :  
Description
Running the VM with -XX:+Verbose prints dozens of register allocator debug messages even if no additional flag like -XX:+PrintOpto is specified. 

-XX:+Verbose should only "Print additional debugging information from other modes" but should not print anything on its own.

RA attempts to clone node with anti_dependence:
 301	testN_mem_reg0	===  2308  40  4016  [[ 300 ]] #16/0x0000000000000010narrowoop: NULL  Type:int:-1..1
 300	cmovI_reg	=== _  301  3037  3038  [[ 312  299 ]] e  Type:int !jvms: java.lang.String::isLatin1 @ bci:10 java.lang.String::charAt @ bci:1 sun.invoke.util.Wrapper::hashPrim @ bci:17 sun.invoke.util.Wrapper::findPrimitiveType @ bci:4 sun.invoke.util.Wrapper::forPrimitiveType @ bci:1 java.lang.invoke.LambdaForm$BasicType::basicType @ bci:12 java.lang.invoke.MethodHandleImpl::makePairwiseConvertByEditor @ bci:154

into block:
B22: #	B23 B453 <- N2222  Freq: 0.756412 IDom: 20/#7 RegPressure: 6 IHRP Index: 9 FRegPressure: 0 FHRP Index: 9
 2308	Region	===  2308  275  [[ 2308  273  295  301  305  309 ]]   Type:control
 4016	InputToRematerializationSpillCopy	=== _  3034  [[ 301 ]]   Type:narrowoop: java/lang/Object:BotPTR *[int:>=0]:BotPTR *
 301	testN_mem_reg0	===  2308  40  4016  [[ 300 ]] #16/0x0000000000000010narrowoop: NULL  Type:int:-1..1
 3037	loadConI	===  11  [[ 300 ]] #1/0x00000001  Type:int:1
 3038	loadConI0	===  11  [[ 3039  300 ]] #0/0x00000000  Type:int:0

[...]
Comments
The problem is in the clone_node() code introduced by JDK-6973329. It should check for PrintOpto && WizardMode in addition to Verbose.
15-03-2016

ILW = too verbose debug output, if debug flag is set, no workaround = LMH = P5
15-03-2016