[PATCH] D74436: Change clang option -ffp-model=precise to select ffp-contract=on

[Jinsong Ji via cfe-commits]

Thanks Melanie.

I have pushed one fix to test-suite to explicitly add -ffp-contract=off to
unblock our internal buildbot for now.
https://github.com/llvm/llvm-test-suite/commit/c04a7178a3a50fe919964df59b041c5671db50f7

Our buildbot are OK now.

I think you can proceed as long as the change is intended and reasonable.
Thanks.


Best,

Jinsong Ji (纪金松), PhD.

XL/LLVM on Power Compiler Development
E-mail: jji at us.ibm.com



From:	"Blower, Melanie I" <melanie.blower at intel.com>
To:	"reviews+D74436+public+e2b40a7853ffb354 at reviews.llvm.org"
            <reviews+D74436+public+e2b40a7853ffb354 at reviews.llvm.org>,
            "lebedev.ri at gmail.com" <lebedev.ri at gmail.com>,
            "rjmccall at gmail.com" <rjmccall at gmail.com>,
            "sepavloff at gmail.com" <sepavloff at gmail.com>
Cc:	"maskray at google.com" <maskray at google.com>, "jji at us.ibm.com"
            <jji at us.ibm.com>, "david.bolvansky at gmail.com"
            <david.bolvansky at gmail.com>, "martin at martin.st"
            <martin at martin.st>, "Wang, Pengfei" <pengfei.wang at intel.com>,
            "wuzish at cn.ibm.com" <wuzish at cn.ibm.com>,
            "nemanja.i.ibm at gmail.com" <nemanja.i.ibm at gmail.com>,
            "kit.barton at gmail.com" <kit.barton at gmail.com>,
            "cfe-commits at lists.llvm.org" <cfe-commits at lists.llvm.org>,
            "mlekena at skidmore.edu" <mlekena at skidmore.edu>,
            "blitzrakete at gmail.com" <blitzrakete at gmail.com>,
            "shenhan at google.com" <shenhan at google.com>,
            "peter.waller at arm.com" <peter.waller at arm.com>
Date:	02/14/2020 10:34 AM
Subject:	[EXTERNAL] RE: [PATCH] D74436: Change clang option
            -ffp-model=precise to select ffp-contract=on



I reverted MaskRay's "reland" since the original patch is causing trouble
on PowerPC, check-all is passing on my box.  Sorry for the trouble.

> -----Original Message-----
> From: Andy Kaylor via Phabricator <reviews at reviews.llvm.org>
> Sent: Thursday, February 13, 2020 9:20 PM
> To: Blower, Melanie I <melanie.blower at intel.com>; lebedev.ri at gmail.com;
> rjmccall at gmail.com; sepavloff at gmail.com
> Cc: maskray at google.com; jji at us.ibm.com; david.bolvansky at gmail.com;
> martin at martin.st; Wang, Pengfei <pengfei.wang at intel.com>;
> wuzish at cn.ibm.com; nemanja.i.ibm at gmail.com; kit.barton at gmail.com; cfe-
> commits at lists.llvm.org; mlekena at skidmore.edu; blitzrakete at gmail.com;
> shenhan at google.com; peter.waller at arm.com
> Subject: [PATCH] D74436: Change clang option -ffp-model=precise to select
ffp-
> contract=on
>
> andrew.w.kaylor added a subscriber: MaskRay.
> andrew.w.kaylor added a comment.
>
> In D74436#1875386 <
https://urldefense.proofpoint.com/v2/url?u=https-3A__reviews.llvm.org_D74436-231875386&d=DwIFAg&c=jf_iaSHvJObTbx-siA1ZOg&r=DvnnfavFQBGT2CDyHzTr_Q&m=cvHv8MkmryQUMVKDW_JEP3rPsAVn_T77lN-oqkY9X2Y&s=4moq7_F2LQUHDL0EsCHrNKUtm43d0NQb2Fmh4CISYOM&e=
 >, @thakis
> wrote:
>
> > The revert of this breaks tests everywhere, as far as I can tell.
>
>
> It looks like something strange happened with the revert:
>
> > clang-11: warning: overriding '-ffp-model=strict' option with '-ffp-
> model=strict' [-Woverriding-t-option]
>
> I believe the problem is that the original change that was being reverted
> contained this:
>
>   clang/lib/Driver/ToolChains/Clang.cpp
>   @@ -2768,7 +2766,7 @@ static void RenderFloatingPointOptions(const
> ToolChain &TC, const Driver &D,
>           !AssociativeMath && !ReciprocalMath &&
>           SignedZeros && TrappingMath && RoundingFPMath &&
>           DenormalFPMath != llvm::DenormalMode::getIEEE() &&
>   +        FPContract.empty())
>   -        (FPContract.equals("off") || FPContract.empty()))
>
> But sometime in the land-revert-land-revert cycle the line above that
changed,
> causing the merge to miss this change in the most recent revert. I see
that
> @MaskRay has since re-landed this change set, but it's going to cause
problems
> for PowerPC. If someone needs to revert this yet again, I think it can be
safely
> done by recovering the change above.
>
> Apologies for the mess!
>
>
> Repository:
>   rG LLVM Github Monorepo
>
> CHANGES SINCE LAST ACTION
>
https://urldefense.proofpoint.com/v2/url?u=https-3A__reviews.llvm.org_D74436_new_&d=DwIFAg&c=jf_iaSHvJObTbx-siA1ZOg&r=DvnnfavFQBGT2CDyHzTr_Q&m=cvHv8MkmryQUMVKDW_JEP3rPsAVn_T77lN-oqkY9X2Y&s=x-uw-PdxKFtF2QXI5p8pFIGwDP53ma6WcFfJSt7NiPY&e=

>
>
https://urldefense.proofpoint.com/v2/url?u=https-3A__reviews.llvm.org_D74436&d=DwIFAg&c=jf_iaSHvJObTbx-siA1ZOg&r=DvnnfavFQBGT2CDyHzTr_Q&m=cvHv8MkmryQUMVKDW_JEP3rPsAVn_T77lN-oqkY9X2Y&s=VJzMi9ZvFzcqz_BCC84nlLx_A4agCXEmi9bNsJMnkJQ&e=

>
>



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