[llvm-commits] [Review request][Win64] Use pushq/popq GPRs in function prologue/epilogue

[Chris Lattner]

Hi Takumi,

Evan said (verbally) that this looks ok to him, go ahead and commit it, thanks!

-Chris

On Feb 21, 2011, at 6:23 PM, NAKAMURA Takumi wrote:

> Ping.
> 
> 
> On Fri, Feb 18, 2011 at 2:02 PM, NAKAMURA Takumi <geek4civic at gmail.com> wrote:
>> Ping.
>> 
>> It would also resolve potential issue if other x86-64 targets had a
>> new calling conversions to preserve XMMs.
>> 
>> ...Takumi
>> 
>> 
>> On Mon, Feb 7, 2011 at 8:49 PM, NAKAMURA Takumi <geek4civic at gmail.com> wrote:
>>> Anton,
>>> 
>>> I attached an updated patch, refined and comments added, thank you.
>>> It is at; https://github.com/chapuni/LLVM/commit/8da7419f8170e5a11063eb8e992ecb1ad40f9f6a
>>> 
>>> 
>>> On the github, Anton wrote;
>>>> View Commit: https://github.com/chapuni/LLVM/commit/d719f1b1ba5f01823e00904c1599adf356089a1d
>>> 
>>>> This will pessimize non-win64 targets. Basically, the problem is that you cannot use pushq/popq for high xmm regs, which are callee-saved on win64-only (but not on linux / darwin, for example).
>>> 
>>> I thought the patch does not affect to non-win64 targets, but it might
>>> be dubious to check whether regs are GPR or not.
>>> I rewrote checking expressions.
>>> 
>>> I am sorry if I missed your point.
>>> 
>>>> Another problem is function prologue emission. Have you verified that you always have proper stack frame? Even in case when high xmm regs (xmm5, etc.) are spilled?
>>> 
>>> As far as spiller emits in order [pushq GPRs...] and [mov xmm to fp],
>>> and restorer emits in order [mov xmm from fp] and [popq GPRs],
>>> emitPrologue() and emitEpilogue() will emit adjusting %rsp onto proper place.
>>> And I can expect spiller can place XMMs i128 aligned.
>>> 
>>> ; for example
>>> define void @foo() nounwind {
>>> entry:
>>>  tail call void (...)* @bar() nounwind
>>>  tail call void asm sideeffect "nop",
>>> "~{si},~{di},~{xmm13},~{xmm11},~{xmm15},~{dirflag},~{fpsr},~{flags}"()
>>> nounwind
>>>  ret void
>>> }
>>> declare void @bar(...)
>>> 
>>> #### -mtriple=x86_64-mingw32
>>> foo:
>>>        pushq   %rsi
>>>        pushq   %rdi
>>>        subq    $88, %rsp
>>>        movaps  %xmm15, 32(%rsp)        # 16-byte Spill
>>>        movaps  %xmm13, 48(%rsp)        # 16-byte Spill
>>>        movaps  %xmm11, 64(%rsp)        # 16-byte Spill
>>>        callq   bar
>>>        #APP
>>>        nop
>>>        #NO_APP
>>>        movaps  64(%rsp), %xmm11        # 16-byte Reload
>>>        movaps  48(%rsp), %xmm13        # 16-byte Reload
>>>        movaps  32(%rsp), %xmm15        # 16-byte Reload
>>>        addq    $88, %rsp
>>>        popq    %rdi
>>>        popq    %rsi
>>>        ret
>>> 
>>> And also, I have checked to build clang by 3 stage.
>>> (x64-clang can build and test clang and llvm)
>>> 
>>> 
>>> ...Takumi
>>> 
>> 
> 
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