RFR: 8315931: RISC-V: xxxMaxVectorTestsSmokeTest fails when using RVV

[Fei Yang]

On Tue, 12 Sep 2023 11:06:45 GMT, Gui Cao <gcao at openjdk.org> wrote:

> Hi, This patch fixes an error when qemu enabled the parameter rvv_ta_all_1s=true. The cause for the error is that the number of set lanes here may be smaller than Matcher::vector_length(this), then this vector width is not set correctly. this in turn causes the width of the returned vector length to be less than the expected length. together with these two options for QEMU, this resulted in the use of unintended vector element values.
> 
> https://github.com/openjdk/jdk/blob/94800781eae192d3e82f5635d4aad165f11eabc1/src/hotspot/cpu/riscv/riscv_v.ad#L3510
> ### Testing:
> qemu with UseRVV:
> - [x] test/jdk/jdk/incubator/vector (fastdebug)
> 
> qemu with rvv_ma_all_1s=true,rvv_ta_all_1s=true and UseRVV:
> - [x] test/jdk/jdk/incubator/vector (fastdebug)

Looks reasonable to me. @robehn : Could you please help verify if this will also work in your test setup? Thanks.

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

Marked as reviewed by fyang (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15680#pullrequestreview-1622158935