[llvm] r190309 - [ARMv8] Prevent generation of deprecated IT blocks on ARMv8 in Thumb mode.

[Hal Finkel]

[+ Artyom, Tim]

Artyom, Joey pointed out that you're the author of this change, so my question is most-properly to you.

Tim, in the review you said, "Ok. I've had a more detailed look at this now. I can see why it's needed, though..."; so if you recall what is going on and can elaborate, please do.

Thanks,
Hal

----- Original Message -----
> From: "Hal Finkel" <hfinkel at anl.gov>
> To: "Joey Gouly" <joey.gouly at arm.com>
> Cc: llvm-commits at cs.uiuc.edu
> Sent: Thursday, November 21, 2013 9:23:30 AM
> Subject: Re: [llvm] r190309 - [ARMv8] Prevent generation of deprecated IT	blocks	on ARMv8 in Thumb mode.
> 
> Joey,
> 
> This commit seems to have broken self hosting on PPC (only with an
> NDEBUG build, which is why we did not catch it earlier). I can only
> suppose it is the changes to lib/CodeGen/IfConversion.cpp that
> either caused the problem, or triggered an existing PPC backend bug.
> Can you please explain the rationale behind the IfConversion
> changes?
> 
> Thanks in advance,
> Hal
> 
> ----- Original Message -----
> > From: "Joey Gouly" <joey.gouly at arm.com>
> > To: "Joey Gouly" <Joey.Gouly at arm.com>, llvm-commits at cs.uiuc.edu
> > Sent: Monday, September 9, 2013 9:48:02 AM
> > Subject: RE: [llvm] r190309 - [ARMv8] Prevent generation of
> > deprecated IT	blocks	on ARMv8 in Thumb mode.
> > 
> > > Author: joey
> > > Date: Mon Sep  9 09:21:49 2013
> > > New Revision: 190309
> > >
> > > URL: http://llvm.org/viewvc/llvm-project?rev=190309&view=rev
> > > Log:
> > > [ARMv8] Prevent generation of deprecated IT blocks on ARMv8 in
> > > Thumb mode.
> > > IT blocks can only be one instruction lonf, and can only contain
> > > a
> > > subset
> > of
> > > the 16 instructions.
> > 
> > Sorry, the commit message here should have read "the 16-bit
> > instructions".
> > 
> > 
> > 
> > 
> > 
> > _______________________________________________
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> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> > 
> 
> --
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory