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Bug ID: 7107042 assert(no_dead_loop) failed: dead loop detected
7107042 : assert(no_dead_loop) failed: dead loop detected

Details
Type:
Bug
Submit Date:
2011-11-01
Status:
Closed
Updated Date:
2012-10-01
Project Name:
JDK
Resolved Date:
2012-01-23
Component:
hotspot
OS:
generic
Sub-Component:
compiler
CPU:
generic
Priority:
P4
Resolution:
Fixed
Affected Versions:
hs23,8-pool
Fixed Versions:
hs23

Related Reports
Backport:
JDK-2217948 - assert(no_dead_loop) failed: dead loop detected
Backport:
JDK-2217947 - assert(no_dead_loop) failed: dead loop detected
Duplicate:
JDK-7109987 - SIGSEGV in nmethod::total_size

Sub Tasks

Description
CTW hit this assert after next changes from 7105305:

src/share/vm/oops/constantPoolKlass.cpp	Mon Oct 31 15:43:37 2011
@@ -532,7 +532,7 @@
     if (cp->tag_at(i).is_unresolved_klass()) {
       // This will force loading of the class
       klassOop klass = cp->klass_at(i, CHECK);
-      if (klass->is_instance()) {
+      if (klass->klass_part()->oop_is_instance()) {
         // Force initialization of class
         instanceKlass::cast(klass)->initialize(CHECK);
       }

Comments
EVALUATION

http://hg.openjdk.java.net/lambda/lambda/hotspot/rev/670a74b863fc
2012-03-22 
EVALUATION

See main CR
2011-11-30 
EVALUATION

http://hg.openjdk.java.net/hsx/hotspot-emb/hotspot/rev/670a74b863fc
2011-11-29 
EVALUATION

http://hg.openjdk.java.net/hsx/hotspot-rt/hotspot/rev/670a74b863fc
2011-11-15 
EVALUATION

http://hg.openjdk.java.net/hsx/hotspot-comp/hotspot/rev/670a74b863fc
2011-11-09 
EVALUATION

Late inlining and IGVN may cut off part of ideal graph which become dead. But dead code may stay in graph and still be reachable from data nodes (for example constants). Region::Ideal() has code to kill not reachable from method's start dead code if Region node has only one input (second input path was cut off). But it can't eliminate a Region node which has two or more live inputs which are loop's back edges. EA may create dead loop Phi nodes if a scalar replaceable allocation is referenced inside such dead loops.

Used dead nodes elimination code in PhaseIdealLoop before executing EA. But do not execute any loop optimizations to avoid ideal graph reshaping before EA.

Also removed dead nodes from macro_nodes list in remove_useless_nodes().


During testing I hit several other problems and fixed them:

Added missed failing() check after each late inline.

Added missed parenthesis for Verbose output of CMOVE nodes.

A switch value for indirect jumps could be shared but the matcher's code which detects it was skipped since incorrect state (Visit instead of Pre_Visit) was used.

Split instance field load through Phi optimization was executed before Phi node is processed.

Use PrintCompilation2 instead of PrintInlining flag to print compilation data after compilation is finished. Change PrintCompilation2 to diagnostic flag and replace it in previous usage (only one) with WizardMode flag. 

Fixed 7109987 problem.
2011-11-09 
EVALUATION

It seems dead loop phi is created during EA:

[t@45 l@45]: print orig_phi->dump(2)
 7147   Phi     ===  7145  7365  7327  [[ 7243  7203  7467  7200  7163  7198  7172  7182  7223  7235 ]]  #memory  Memory: @BotPTR *+bot, idx=Bot; !orig=[7215] !jvms: functionParser::Q3119 @ bci:2077
 7395   Proj    ===  7379  [[ 7467  7243  818  7457  7454  7417  7452  7426  7436 ]] #2  Memory: @BotPTR *+bot, idx=Bot; !jvms: functionParser::Q3119 @ bci:2074
 7241   Region  ===  7241  7462  7240  [[ 7241  7259  7242  7243  7262  8784 ]]  !jvms: functionParser::Q3119 @ bci:2021
 7270   AddI    === _  7268  42  [[ 7280  7273  7272 ]]  !jvms: functionParser::Q3515 @ bci:12 functionParser::Q3119 @ bci:2026
 971    AddP    === _  105  105  197  [[ 972  3253  3262  3356  3365  3369  3436  3445  3720  3729  3780  3789  3939  3948  3951  4014  4023  4026  7163  7172  7259  7268  7272  7417  7426  7481  7490  7541  7550  7614  7624  7627  7687  7697  7700  7762  7772  7775  7834  7844  7847 ]]  !jvms: functionParser::Q3519 @ bci:3 functionParser::Q3119 @ bci:72
 7264   IfFalse ===  7262  [[ 7277  7268  7272 ]] #0 !jvms: functionParser::Q3515 @ bci:3 functionParser::Q3119 @ bci:2026
 7263   IfTrue  ===  7262  [[ 7249 ]] #1 !jvms: functionParser::Q3515 @ bci:3 functionParser::Q3119 @ bci:2026
 7278   IfTrue  ===  7277  [[ 7249  7296 ]] #1 !jvms: functionParser::Q3515 @ bci:15 functionParser::Q3119 @ bci:2026
 7243   Phi     ===  7241  7395  7147  [[ 7382  7352  7343  7314  7259  7309  7268  7272  7275  7305  7252  7299  7297 ]]  #memory  Memory: @BotPTR *+bot, idx=Bot; !jvms: functionParser::Q3119 @ bci:2021
 7272   StoreI  ===  7264  7243  971  7270  [[ 7297  7275  7296  8783 ]]  @int[int:>=0]:exact+any *, idx=4;  Memory: @int[int:1]:NotNull:exact[0] *,iid=88, idx=35; !jvms: functionParser::Q3515 @ bci:14 functionParser::Q3119 @ bci:2026
 7249   Region  ===  7249  7278  7263  [[ 7249  7297  7302  7253  8783 ]]  !jvms: functionParser::Q3119 @ bci:2026
 7297   Phi     ===  7249  7272  7243  [[ 7252  7305  7314  7382  7343  7352 ]]  #memory  Memory: @int[int:>=0]:exact+any *, idx=4; !orig=7251 !jvms: functionParser::Q3119 @ bci:2026

[t@45 l@45]: print result->dump() 
8783   Phi     ===  7249 _ _  [[]]  #memory  Memory: @int[int:1]:NotNull:exact+any *,iid=88, idx=35; !orig=7297,7251 !jvms: functionParser::Q3119 @ bci:2026

[t@45 l@45]: print mem->dump()
 7272   StoreI  ===  7264  7243  971  7270  [[ 7297  7275  7296 ]]  @int[int:>=0]:exact+any *, idx=4;  Memory: @int[int:1]:NotNull:exact[0] *,iid=88, idx=35; !jvms: functionParser::Q3515 @ bci:14 functionParser::Q3119 @ bci:2026


[t@45 l@45]: print mem->dump(1)
 8785   Phi     ===  7145  8783  8783  [[ 8784 ]]  #memory  Memory: @int[int:1]:NotNull:exact+any *,iid=88, idx=35; !orig=7147,[7215] !jvms: functionParser::Q3119 @ bci:2077
 8783   Phi     ===  7249  7272 _  [[ 7343  8784  7305  8785  7252  8785 ]]  #memory  Memory: @int[int:1]:NotNull:exact+any *,iid=88, idx=35; !orig=7297,7251 !jvms: functionParser::Q3119 @ bci:2026
 7241   Region  ===  7241  7462  7240  [[ 7241  7259  7242  7243  7262  8784 ]]  !jvms: functionParser::Q3119 @ bci:2021
 8784   Phi     ===  7241  8783  8785  [[]]  #memory  Memory: @int[int:1]:NotNull:exact+any *,iid=88, idx=35; !orig=7243 !jvms: functionParser::Q3119 @ bci:2021


[t@45 l@45]: print result->dump(1)
 8784   Phi     ===  7241  8783  8785  [[ 8783 ]]  #memory  Memory: @int[int:1]:NotNull:exact+any *,iid=88, idx=35; !orig=7243 !jvms: functionParser::Q3119 @ bci:2021
 7272   StoreI  ===  7264  7243  971  7270  [[ 7297  7275  7296  8783 ]]  @int[int:>=0]:exact+any *, idx=4;  Memory: @int[int:1]:NotNull:exact[0] *,iid=88, idx=35; !jvms: functionParser::Q3515 @ bci:14 functionParser::Q3119 @ bci:2026
 7249   Region  ===  7249  7278  7263  [[ 7249  7297  7302  7253  8783 ]]  !jvms: functionParser::Q3119 @ bci:2026
 8783   Phi     ===  7249  7272  8784  [[ 7343  8784  7305  8785  7252  8785 ]]  #memory  Memory: @int[int:1]:NotNull:exact+any *,iid=88, idx=35; !orig=7297,7251 !jvms: functionParser::Q3119 @ bci:2026
2011-11-01


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