git: openjdk/jdk: 8252219: C2: Randomize IGVN worklist for stress testing

[Tobias Hartmann]

Changeset: fed3636f
Author:    Roberto Castaneda Lozano <roberto.castaneda.lozano at oracle.com>
Committer: Tobias Hartmann <thartmann at openjdk.org>
Date:      2020-09-28 06:44:58 +0000
URL:       https://git.openjdk.java.net/jdk/commit/fed3636f

8252219: C2: Randomize IGVN worklist for stress testing

Add 'StressIGVN' option to let C2 randomize IGVN worklist order. When enabled,
the worklist is shuffled before each main run of the IGVN loop. Also add
'StressSeed=N' option to specify the seed. If the seed is not specified, a
random one is generated. In either case, the seed is logged if 'LogCompilation'
is enabled. The new options are declared as production+diagnostic for
consistency with the existing 'StressLCM' and 'StressGCM' options.

Reviewed-by: kvn, chagedorn, thartmann

! src/hotspot/share/opto/c2_globals.hpp
! src/hotspot/share/opto/compile.cpp
! src/hotspot/share/opto/compile.hpp
! src/hotspot/share/opto/phaseX.cpp
! src/hotspot/share/opto/phaseX.hpp
! src/hotspot/share/runtime/os.cpp
! src/hotspot/share/runtime/os.hpp
+ test/hotspot/jtreg/compiler/arguments/TestStressIGVNOptions.java
+ test/hotspot/jtreg/compiler/debug/TestGenerateStressSeed.java
+ test/hotspot/jtreg/compiler/debug/TestStressIGVN.java