JDK-8354222 : TestSubNodeFloatDoubleNegation intermittently failing
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 25
  • Priority: P4
  • Status: Closed
  • Resolution: Duplicate
  • OS: linux
  • CPU: x86
  • Submitted: 2025-04-09
  • Updated: 2025-04-11
  • Resolved: 2025-04-11
Related Reports
Causes :  
JDK-8351515 - C2 incorrectly removes double negation for double and float
Duplicate :  
JDK-8353730 - TestSubNodeFloatDoubleNegation.java fails with native Float16 support
Description
SOme of the IR tests in this class are intermittently failing: compiler.floatingpoint.TestSubNodeFloatDoubleNegation

Failed IR Rules (2) of Methods (1)
----------------------------------
1) Method "public static jdk.incubator.vector.Float16 compiler.floatingpoint.TestSubNodeFloatDoubleNegation.testHalfFloat(jdk.incubator.vector.Float16)" - [Failed IR rules: 2]:
   * @IR rule 1: "@compiler.lib.ir_framework.IR(phase={DEFAULT}, applyIfPlatformAnd={}, applyIfCPUFeatureOr={}, counts={"_#SUB#_", "2"}, applyIfPlatform={"riscv64", "false"}, failOn={}, applyIfPlatformOr={}, applyIfOr={}, applyIfCPUFeatureAnd={}, applyIf={}, applyIfCPUFeature={}, applyIfAnd={}, applyIfNot={})"
     > Phase "PrintIdeal":
       - counts: Graph contains wrong number of nodes:
         * Constraint 1: "(\\d+(\\s){2}(Sub(I|L|F|D|HF).*)+(\\s){2}===.*)"
           - Failed comparison: [found] 3 = 2 [given]
             - Matched nodes (3):
               * 326  SubHF  === _ 560 325  [[ 327 479 ]]  !orig=[478] !jvms: Float16::valueOf @ bci:5 (line 329) Float16::subtract @ bci:9 (line 1137) TestSubNodeFloatDoubleNegation::testHalfFloat @ bci:9 (line 65)
               * 443  SubF  === _ 561 442  [[ 607 ]]  !jvms: Float16::subtract @ bci:8 (line 1137) TestSubNodeFloatDoubleNegation::testHalfFloat @ bci:12 (line 63)
               * 479  SubHF  === _ 560 326  [[ 480 ]]  !jvms: Float16::valueOf @ bci:5 (line 329) Float16::subtract @ bci:9 (line 1137) TestSubNodeFloatDoubleNegation::testHalfFloat @ bci:12 (line 63)
   * @IR rule 2: "@compiler.lib.ir_framework.IR(phase={DEFAULT}, applyIfPlatformAnd={}, applyIfCPUFeatureOr={}, counts={"_#SUB#_", "2"}, applyIfPlatform={}, failOn={}, applyIfPlatformOr={}, applyIfOr={}, applyIfCPUFeatureAnd={}, applyIf={}, applyIfCPUFeature={"zfh", "false"}, applyIfAnd={}, applyIfNot={})"
     > Phase "PrintIdeal":
       - counts: Graph contains wrong number of nodes:
         * Constraint 1: "(\\d+(\\s){2}(Sub(I|L|F|D|HF).*)+(\\s){2}===.*)"
           - Failed comparison: [found] 3 = 2 [given]
             - Matched nodes (3):
               * 326  SubHF  === _ 560 325  [[ 327 479 ]]  !orig=[478] !jvms: Float16::valueOf @ bci:5 (line 329) Float16::subtract @ bci:9 (line 1137) TestSubNodeFloatDoubleNegation::testHalfFloat @ bci:9 (line 65)
               * 443  SubF  === _ 561 442  [[ 607 ]]  !jvms: Float16::subtract @ bci:8 (line 1137) TestSubNodeFloatDoubleNegation::testHalfFloat @ bci:12 (line 63)
               * 479  SubHF  === _ 560 326  [[ 480 ]]  !jvms: Float16::valueOf @ bci:5 (line 329) Float16::subtract @ bci:9 (line 1137) TestSubNodeFloatDoubleNegation::testHalfFloat @ bci:12 (line 63)
Comments
Closing as duplicate of JDK-8353730. Thanks for reporting it anyways!
11-04-2025
So it's a "Intel(R) Xeon(R) Platinum 8488C" which is a "Sapphire Rapids" and according to https://en.wikipedia.org/wiki/Sapphire_Rapids it has support for AVX512-FP16. Looks like a dup of JDK-8353730 to me then, right?
11-04-2025
I attached a file containing a more detailed CPU description.
10-04-2025
These are the CPU features/flags: flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq monitor ssse3 fma cx16 pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch invpcid_single ssbd ibrs ibpb stibp ibrs_enhanced fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid avx512f avx512dq rdseed adx smap avx512ifma clflushopt clwb avx512cd sha_ni avx512bw avx512vl xsaveopt xsavec xgetbv1 xsaves avx512_bf16 wbnoinvd ida arat avx512vbmi umip pku ospke waitpkg avx512_vbmi2 gfni vaes vpclmulqdq avx512_vnni avx512_bitalg tme avx512_vpopcntdq rdpid cldemote movdiri movdir64b md_clear serialize flush_l1d arch_capabilities
10-04-2025
[~cslucas], does your machine have the CPU feature AVX512-FP16? If yes, then this is definitely a duplicate.
10-04-2025
Manuel, could you please check if this is a duplicate of JDK-8353730?
10-04-2025