RFR: 8228622: [lworld] Ineffective codegeneration for flattened arrays checks causes large performance regression on List iteration

[Tobias Hartmann]

Hi Roland,

all tests passed!

Thanks,
Tobias

On 23.09.19 14:57, Roland Westrelin wrote:
> 
>> Now fails with -XX:TieredStopAtLevel=1:
>> Caused by: java.lang.RuntimeException: assertTrue: expected true, was false
>> 	at jdk.test.lib.Asserts.fail(Asserts.java:594)
>> 	at jdk.test.lib.Asserts.assertTrue(Asserts.java:486)
>> 	at jdk.test.lib.Asserts.assertTrue(Asserts.java:472)
>> 	at compiler.valhalla.valuetypes.TestLWorld.test93_verifier(TestLWorld.java:2298)
>> 	... 6 more
> 
> Thanks for running tests. Another try, see below...
> 
> Roland.
> 
> diff -r 8bc0adf95445 -r e989f1bfd6a4 src/hotspot/share/opto/callnode.cpp
> --- a/src/hotspot/share/opto/callnode.cpp	Fri Sep 20 17:19:14 2019 +0200
> +++ b/src/hotspot/share/opto/callnode.cpp	Mon Sep 23 10:48:18 2019 +0200
> @@ -1237,7 +1237,7 @@
>    igvn->register_new_node_with_optimizer(unc);
>    
>    Node* ctrl = phase->transform(new ProjNode(unc, TypeFunc::Control));
> -  Node* halt = phase->transform(new HaltNode(ctrl, alloc->in(TypeFunc::FramePtr)));
> +  Node* halt = phase->transform(new HaltNode(ctrl, alloc->in(TypeFunc::FramePtr), "uncommon trap returned which should never happen"));
>    phase->C->root()->add_req(halt);
>  
>    return true;
> diff -r 8bc0adf95445 -r e989f1bfd6a4 test/hotspot/jtreg/compiler/valhalla/valuetypes/TestLWorld.java
> --- a/test/hotspot/jtreg/compiler/valhalla/valuetypes/TestLWorld.java	Fri Sep 20 17:19:14 2019 +0200
> +++ b/test/hotspot/jtreg/compiler/valhalla/valuetypes/TestLWorld.java	Mon Sep 23 10:48:18 2019 +0200
> @@ -2250,10 +2250,7 @@
>              }
>          }
>          
> -        Object v = array[0];
> -        if (v instanceof Integer) {
> -        }
> -        return v;
> +        return (Integer)array[0];
>      }
>  
>      @DontCompile
> @@ -2275,9 +2272,7 @@
>              }
>          }
>          
> -        Object v = array[0];
> -        if (v instanceof Integer) {
> -        }
> +        Object v = (Integer)array[0];
>          return v;
>      }
>  
> @@ -2291,13 +2286,16 @@
>          } else {
>              Object[] array = new Test92Value[1];
>              Method m = tests.get("TestLWorld::test93");
> -            int extra = 2;
> +            int extra = 3;
>              for (int j = 0; j < extra; j++) {
>                  for (int i = 0; i < 10; i++) {
> -                    test93(array);
> +                    try {
> +                        test93(array);
> +                    } catch (ClassCastException cce) {
> +                    }
>                  }
>                  boolean compiled = isCompiledByC2(m);
> -                Asserts.assertTrue(!USE_COMPILER || XCOMP || TEST_C1 || compiled == (j == extra-1));
> +                Asserts.assertTrue(!USE_COMPILER || XCOMP || TEST_C1 || compiled || (j != extra-1));
>                  if (!compiled) {
>                      enqueueMethodForCompilation(m, COMP_LEVEL_FULL_OPTIMIZATION);
>                  }
>