[cfe-commits] [llvm-commits] Fix bug 11753 - Incorrect code generated for 64bit types on ARM

[Weiming Zhao]

Hi Sandeep,

I can't find the spec for aps-gnu. But my tests show that, in term of
passing i64, it requires an aligned register pair, which is the same
requirement in aapcs. 
This why I mentions the aapcs spec. 

Thanks,
Weiming


-----Original Message-----
From: Sandeep Patel [mailto:deeppatel1987 at gmail.com]
Sent: Thursday, March 29, 2012 6:17 PM
To: Weiming Zhao
Cc: "'cfe-commits at cs.uiuc.edu.'"@pps04.cites.illinois.edu;
llvm-commits at cs.uiuc.edu
Subject: Re: [llvm-commits] Fix bug 11753 - Incorrect code generated for
64bit types on ARM

You're testing apcs-gnu, but referring to the aapcs spec.

i64 parameter alignment should already be handled by the CCIfAlign<> parts
of ARMCallingConv.td in the backend for AAPCS.

deep

On Thu, Mar 29, 2012 at 9:22 PM, Weiming Zhao <weimingz at codeaurora.org>
wrote:
> Hello,
>
>
>
> This is a bug fix for Clang. It fixes bug 11753 - Incorrect code 
> generated for 64bit types on ARM.
>
>
>
> ARM calling convention requires a double-word sized type is passed in 
> two consecutive registers (r0,r1 or r2,r3). (See 
> http://infocenter.arm.com/help/topic/com.arm.doc.ihi0042d/IHI0042D_aap
> cs.pdf
> 5.1.1.1, page 16).
>
>
>
> However, currently, for apcs-gnu ABI, such constraint has not been 
> implemented.
>
>
>
> This patch fixes this issue by padding a register if needed. This 
> solution is similar to a recent fix for MIPS.
>
>
>
> I’m attaching my patch
> (0001-Fix-the-missed-register-padding-for-passing-long-lon.patch), a 
> new unit test case (0002-unnit-test.patch), as well as the running 
> results of unit test (unit_test_after.txt) and the test suite 
> (testsuite.report.simple.txt).  My patch doesn’t cause any errors.
>
>
>
> I also uploaded the same files to the bugzilla.
>
>
>
> Please kindly review the codes.
>
>
>
> Thanks,
>
> Weiming
>
>
>
>
>
>
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