RFR: 8020282: Generated code quality: redundant LEAs in the chained dereferences [v8]

[Manuel Hässig]

On Wed, 18 Jun 2025 16:56:37 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> src/hotspot/cpu/x86/peephole_x86_64.cpp line 359:
>> 
>>> 357: 
>>> 358:   // Remove spill for the decode if the spill node does not have any other uses.
>>> 359:   if (is_spill && decode_spill->outcnt() == 1 && block->contains(decode_spill)) {
>> 
>> You can rearrange this to avoid forward declaration of `decode_spill`:
>> 
>> 
>>   if (is_spill) {
>>     MachNode* decode_spill = decode->in(1)->as_Mach();
>>     If (decode_spill->outcnt() == 1 && block->contains(decode_spill)) {
>
> Or you concern that inputs of `decode` could be modified and you cached it?

Thank you for pointing this out. I was not trying to cache it. Reorganized in [da3f007](https://github.com/openjdk/jdk/pull/25471/commits/da3f007cb786b5a3efcdb155abcf73d8dbcee8af)

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

PR Review Comment: https://git.openjdk.org/jdk/pull/25471#discussion_r2155122423