RFR: 8351156: C1: Remove FPU stack support after 32-bit x86 removal

[Aleksey Shipilev]

On Thu, 27 Mar 2025 16:35:01 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

> Which is wrong I think. It should be "FPR". May be file RFE to rename `LIR_Opr::is_*_fpu()` methods to `LIR_Opr::is_*_fpr()`

Yes, that would be more accurate. Remains to be seen how intrusive is this rename.

> src/hotspot/share/c1/c1_LinearScan.cpp line 2662:
> 
>> 2660: 
>> 2661:   } else if (opr->is_single_fpu()) {
>> 2662: #if defined(AMD64)
> 
> Which platform uses this code? May be check #if for it.

This is generic C1 linear scan. This assert is for x86_64: it is the same assert that we already have. I only translated `#elif` to `#if`.

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PR Comment: https://git.openjdk.org/jdk/pull/24274#issuecomment-2758720158
PR Review Comment: https://git.openjdk.org/jdk/pull/24274#discussion_r2017114008