[aarch64-port-dev ] FW: RFR: 8257137: Revise smov and umov in aarch64 assembler [v4]

[Hao Sun]

Can anyone help to review this patch?
 Thanks a lot.

-----Original Message-----
From: hotspot-compiler-dev <hotspot-compiler-dev-retn at openjdk.java.net> On Behalf Of Hao Sun
Sent: Thursday, February 25, 2021 9:28 AM
To: hotspot-compiler-dev at openjdk.java.net
Subject: Re: RFR: 8257137: Revise smov and umov in aarch64 assembler [v4]

> 1. Both smov and umov lack of checking the register type validity.
>    Register type must be 'B', 'H' or 'S' for smov [1].
>    Register type can NOT be 'Q' for umov [2].
>    Such checks are added.
>
> 2. smov and umov have different explanations on 'Q' field, i.e. bit 30
> of the insturction, but current assembler implementation mixed it up.
>    For umov, 'Q' field can only be set when register type 'D' is given
>    [2]. However, this field of smov must be set for register type 'S'
>    [1], that is, 'Q' field can be optional for register type 'B' or 'H'.
>
>    Current implementation only took the umov scenario into account. As a
>    result, runtime error ILL_ILLOPN would occur if 'smov(Register,
>    FloatRegister, S, index)' is used.
>
>    We put them into two separate functions and make 'Q' field always set
>    for smov. That means 'SMOVX' (64-bit register variant) is generated
>    for all cases since it's compatible with our current usages of 'SMOVW'.
>    Existing usages of smov have been double checked and this patch does
>    not affect them.
>
> 3. Smoke tests are also added.
>
> [1].
> https://developer.arm.com/docs/ddi0602/f/simd-and-floating-point-instr
> uctions-alphabetic-order/smov-signed-move-vector-element-to-general-pu
> rpose-register [2].
> https://developer.arm.com/docs/ddi0602/f/simd-and-floating-point-instr
> uctions-alphabetic-order/umov-unsigned-move-vector-element-to-general-
> purpose-register
>
>
> Note that Jtreg tier1 and jdk::tier3 have been tested and all tests passed without new failures.

Hao Sun has updated the pull request incrementally with one additional commit since the last revision:

  Code style: add spaces between operands

  add spaces between operands

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1586/files
  - new: https://git.openjdk.java.net/jdk/pull/1586/files/ba69f500..b624a6b4

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1586&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1586&range=02-03

  Stats: 75 lines in 2 files changed: 2 ins; 0 del; 73 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1586.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1586/head:pull/1586

PR: https://git.openjdk.java.net/jdk/pull/1586
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