https://github.com/openjdk/jdk/blame/master/test/hotspot/jtreg/compiler/codegen/TestGCMStorePlacement.java

This test takes about 50sec in tier1, and is among the slowest compiler test in tier1.

Try this:
1) check which @run take the most time.
2) lower the iterations, and maybe some threasholds.
3) verify that the same compilations are triggered, OSR and regular.

First analysis:

regularReducible1 - 0.7 sec
regularReducible2 - 9.8 sec
regularReducible3 - 14.3 sec
regularReducible4 - 14.7 sec
osrReducible1 - 10.2 sec
osrReducible2 - 10.2 sec
osrIrreducible1 - 0.7

Getting info of: -XX:CompileCommand=printcompilation,compiler.codegen.TestGCMStorePlacement::*

regularReducible1 - 0.7 sec
    638 509 b 3 compiler.codegen.TestGCMStorePlacement::testRegularReducible1 (34 bytes)
    639 512 b 4 compiler.codegen.TestGCMStorePlacement::testRegularReducible1 (34 bytes)
    645 516 % b 3 compiler.codegen.TestGCMStorePlacement::main @ 218 (436 bytes)
    648 517 b 3 compiler.codegen.TestGCMStorePlacement::main (436 bytes)
    651 518 % b 4 compiler.codegen.TestGCMStorePlacement::testRegularReducible1 @ 12 (34 bytes)
    652 519 % b 3 compiler.codegen.TestGCMStorePlacement::main @ 218 (436 bytes)

regularReducible2 - 9.8 sec
   9359 3531 b compiler.codegen.TestGCMStorePlacement::main (436 bytes)
   9674 3627 b compiler.codegen.TestGCMStorePlacement::testRegularReducible2 (100 bytes)

regularReducible3 - 14.3 sec
  13468 6573 b 3 compiler.codegen.TestGCMStorePlacement::main (436 bytes)
  14074 6770 b 4 compiler.codegen.TestGCMStorePlacement::main (436 bytes)
  14077 6771 b 3 compiler.codegen.TestGCMStorePlacement::testRegularReducible3 (95 bytes)
  14078 6772 b 4 compiler.codegen.TestGCMStorePlacement::testRegularReducible3 (95 bytes)

regularReducible4 - 14.7 sec
  13550 6572 b 3 compiler.codegen.TestGCMStorePlacement::main (436 bytes)
  14142 6769 b 4 compiler.codegen.TestGCMStorePlacement::main (436 bytes)
  14146 6770 b 3 compiler.codegen.TestGCMStorePlacement::testRegularReducible4 (74 bytes)
  14146 6771 b 4 compiler.codegen.TestGCMStorePlacement::testRegularReducible4 (74 bytes)

osrReducible1 - 10.2 sec
   9380 3531 b compiler.codegen.TestGCMStorePlacement::main (436 bytes)
   9692 3627 !b compiler.codegen.TestGCMStorePlacement::testOsrReducible1 (88 bytes)
   9693 3628 b compiler.codegen.TestGCMStorePlacement::bar (38 bytes)
   9695 3632 b compiler.codegen.TestGCMStorePlacement::foo (4 bytes)
   9729 3633 % !b compiler.codegen.TestGCMStorePlacement::testOsrReducible1 @ 13 (88 bytes)

osrReducible2 - 10.2 sec
   9431 3531 b compiler.codegen.TestGCMStorePlacement::main (436 bytes)
   9750 3627 b compiler.codegen.TestGCMStorePlacement::testOsrReducible2 (62 bytes)
   9812 3657 % b compiler.codegen.TestGCMStorePlacement::testOsrReducible2 @ 18 (62 bytes)
   9813 3658 b compiler.codegen.TestGCMStorePlacement::testOsrReducible2 (62 bytes)

osrIrreducible1 - 0.7
    670 508 % b 3 compiler.codegen.TestGCMStorePlacement::testOsrIrreducible1 @ 46 (95 bytes)
    670 509 b 3 compiler.codegen.TestGCMStorePlacement::testOsrIrreducible1 (95 bytes)
    671 510 % b 4 compiler.codegen.TestGCMStorePlacement::testOsrIrreducible1 @ 46 (95 bytes)
    673 511 % b 3 compiler.codegen.TestGCMStorePlacement::testOsrIrreducible1 @ 46 (95 bytes)
    674 512 % b 4 compiler.codegen.TestGCMStorePlacement::testOsrIrreducible1 @ 46 (95 bytes)