[vectorIntrinsics] RFR: 8261394: [vector] Crash with "assert(Matcher::vector_size_supported(elem_bt, length)) failed: length in range"

[Jie Fu]

On Thu, 18 Feb 2021 13:49:35 GMT, Jie Fu <jiefu at openjdk.org> wrote:

>> Looks good to me, but perhaps @sviswa7 may take a look as well?
>
> For ACOSDouble64VectorTests, I think @sviswa7 would like to generate code like this:
> 
> 098     B6: #   out( B14 B7 ) <- in( B5 )  Freq: 0.999977
> 098     # checkcastPP of RBX
> 098     movl    R11, [RBX + #12 (8-bit)]        # compressed ptr ! Field: jdk/internal/vm/vector/VectorSupport$VectorPayload.payload (constant)
> 09c     load_vector XMM0,[R12 + R11 << 3 + #16] (compressed oop addressing)
> 0a3     call_leaf,vector  vector_acos_double64
>         No JVM State Info
>         #
> 
> However, the fix will generate code like this.
> 
> 095     B6: #   out( B18 B7 ) <- in( B5 )  Freq: 0.999977
> 095     movq    R9, RAX # spill
> 098     # checkcastPP of R9
> 098     movq    RDI, jdk/incubator/vector/DoubleVector$$Lambda$27+0x0000000801052e28:exact *    # ptr
> 0a2     movl    RSI, #108       # int
> 0a7     movq    RDX, java/lang/Class:exact *    # ptr
> 0b1     movq    RCX, java/lang/Class:exact *    # ptr
> 0bb     movl    R8, #1  # int
>         nop     # 3 bytes pad for loops and calls
> 0c4     call,static  jdk.internal.vm.vector.VectorSupport::unaryOp
>         # jdk.incubator.vector.DoubleVector::lanewiseTemplate @ bci:71 (line 554) L[0]=_ L[1]=_ L[2]=_
>         # jdk.incubator.vector.Double64Vector::lanewise @ bci:2 (line 273) L[0]=_ L[1]=_
>         # jdk.incubator.vector.Double64Vector::lanewise @ bci:2 (line 41) L[0]=_ L[1]=_
>         # Test::ACOSDouble64VectorTests @ bci:15 (line 10) L[0]=_
>         # OopMap {rbp=Oop off=204/0xcc}
> 
> Maybe, it's OK to call vector_acos_double64 for Double64Vector on x86.
> Thanks.

> @DamonFool is correct, with this change the vector stubs are not being called at all.
> @XiaohongGong @nsjian The correct fix would be as follows:
> diff --git a/src/hotspot/share/opto/vectorIntrinsics.cpp b/src/hotspot/share/opto/vectorIntrinsics.cpp
> index 056c415..b0ac90f 100644
> --- a/src/hotspot/share/opto/vectorIntrinsics.cpp
> +++ b/src/hotspot/share/opto/vectorIntrinsics.cpp
> @@ -253,6 +253,9 @@ bool LibraryCallKit::inline_vector_nary_operation(int n) {
> }
> return false;
> }
> 
> * if (!Matcher::vector_size_supported(elem_bt, num_elem)) {
> * ```
>    return false;
>   ```
> * }
>   }
> 
> // TODO When mask usage is supported, VecMaskNotUsed needs to be VecMaskUseLoad.

This change doesn't call vector_acos_double64 for Double64Vector on x86 either.
But it seems reasonable and better to understand.

Let's push it to fix the bug ASAP.
And I'll check whether we can generate vector_acos_double64 for Double64Vector later.
Thanks.

-------------

PR: https://git.openjdk.java.net/panama-vector/pull/38