RFR: 8256633: Fix product build on Windows+Arm64

[Aleksey Shipilev]

On Thu, 19 Nov 2020 09:17:58 GMT, Bernhard Urban-Forster <burban at openjdk.org> wrote:

> Fix this warning:
> C:\work\openjdk-jdk\src\hotspot\cpu\aarch64\assembler_aarch64.hpp(508): error C2220: the following warning is treated as an error
> C:\work\openjdk-jdk\src\hotspot\cpu\aarch64\assembler_aarch64.hpp(508): warning C4390: ';': empty controlled statement found; is this the intent?
> 
> Thanks to @magicus to bring that to my attention.

src/hotspot/cpu/aarch64/assembler_aarch64.hpp line 509:

> 507:           if (_ext.shift() > 0) {
> 508:             assert(_ext.shift() == (int)size, "bad shift");
> 509:           }

D'oh. So this is semantically the same as:

 assert(_ext.shift() <= 0 || _ext.shift() == (int)size, "bad shift");

...or, if we expect shift to be non-negative:

 assert(_ext.shift() == 0 || _ext.shift() == (int)size, "bad shift");

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PR: https://git.openjdk.java.net/jdk/pull/1312