[llvm-commits] [PATCH][Review Request]Alternative Calling Convention

[Demikhovsky, Elena]

We are calling AVX function from AVX code and pass parameters in YMM. And SSE from SSE and pass parameters in XMM.
There are some differences from standard C conventions that described in LLVM today, but not cross architecture.
That's why we call it "Alternative SIMD".

- Elena

-----Original Message-----
From: Jakob Stoklund Olesen [mailto:stoklund at 2pi.dk] 
Sent: Monday, October 15, 2012 19:01
To: Demikhovsky, Elena
Cc: Commit Messages and Patches for LLVM; Nadav Rotem
Subject: Re: [llvm-commits] [PATCH][Review Request]Alternative Calling Convention


On Oct 14, 2012, at 6:00 AM, "Demikhovsky, Elena" <elena.demikhovsky at intel.com> wrote:

> Hi Jacob,
> 
> Thank you for the review.
> 
> I removed CALL_ALT_SIMD, changed CalleeSavedRegs and added a test for prolog-epilog.
> I specified CSR_64_Alt_SIMD_AVX and CSR_64_Alt_SIMD separately, 
> otherwise, if I specify YMM only, I see correct code on AVX and the 
> both YMM and XMM spill/fill on SSE architecture.

Thanks, Elena.

The code looks good to me now.

Please use a different name for the calling convention, though. "Alt" is not very descriptive.

Since this calling convention causes subtle miscompilations when calling non-AVX code from AVX code, I think it would be a good idea to mention that in the comment.

/jakob

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