RFR: 8291649: multiple tests failing with -Xcomp after JDK-8290034 [v3]

[Kim Barrett]

On Fri, 26 Aug 2022 19:11:55 GMT, John R Rose <jrose at openjdk.org> wrote:

>> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   8291649: Incorporating code changes from Kim and John.
>
> test/hotspot/gtest/opto/test_moveBits.cpp line 77:
> 
>> 75: }
>> 76: 
>> 77: // here is some object code to look at:
> 
> Here's a more useful comment:
> 
> 
> // Here is some object code to look at if we want to do a manual
> // study.  One could find the build file named test_moveBits.o.cmdline
> // and hand-edit the command line to produce assembly code in
> // test_moveBits.s.
> //
> // Or, given the two empty "fence functions", one could do a
> // quick scan like this:
> //
> // $ objdump -D $(find build/*release -name test_moveBits.o) \
> //   | sed -n /start_code_quality/,/end_code_quality/p \
> //   | egrep -B10 bswap  # or grep -B20 cfi_endproc
> 
> void start_code_quality_moveBits() { }
> 
> int16_t code_quality_reverse_bytes_16(int16_t x) {
> …
> 
> int64_t code_quality_reverse_bits_64(int64_t x) {
>   return reverse_bits(x);  // should compile to andq/shrq with 64-bit masks
> }
> 
> void end_code_quality_moveBits() { }

I pushed a small fix, and added @rose00 above suggestion to my mentioned above.

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PR: https://git.openjdk.org/jdk/pull/9987