IV26974: BAD LOOP VERSIONER TEST LEADS TO POOR PERFORMANCE, OR TO A CRASH IN JITTED CODE
Closed as program error.
Error Message: This could be a performance problem, or it could appear as a crash with vmState=0x00000000. . Stack Trace: .
The jit optimization "loop versioner" attempts to make a fast version of a loop that omits certain checks in the loop by performing equivalent checks before the loop starts. If the loop contains an array access using an indexing expression that changes every loop iteration, the optimization can erroneously try to pull that indexing expression out of the loop, resulting in a nonsense check before the loop. This corrupt check can cause control to flow to the slow version of the loop, thereby harming performance; or else the corruption could be so severe that the generated code crashes.
This defect will be fixed in: 6.0.1 SR3 7.0.0 SR2 6.0.0 SR11 5.0.0 SR14 . The loop versioner optimization was fixed so it doesn't try to emit checks based on the array indexing expression under these circumstances.
Reported component name
JAVA 5 JIT
Reported component ID
Last modified date
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fixed component name
JAVA 5 JIT
Fixed component ID
Applicable component levels
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