[llvm] r243057 - fix crash in machine trace metrics due to processing dbg_value instructions (PR24199)

[Robinson, Paul]

Thanks!
--paulr

> -----Original Message-----
> From: hwennborg at google.com [mailto:hwennborg at google.com] On Behalf Of Hans
> Wennborg
> Sent: Thursday, July 30, 2015 10:18 AM
> To: Robinson, Paul; Evan Cheng
> Cc: Sanjay Patel; llvm-commits at cs.uiuc.edu
> Subject: Re: [llvm] r243057 - fix crash in machine trace metrics due to
> processing dbg_value instructions (PR24199)
> 
> Since Evan seems to be unavailable, and this has been in trunk for
> almost a week without issues, I'll go ahead and merge it.
> 
> r243662.
> 
>  - Hans
> 
> 
> On Wed, Jul 29, 2015 at 10:16 AM, Hans Wennborg <hans at chromium.org> wrote:
> > Ping?
> >
> > On Mon, Jul 27, 2015 at 1:25 PM, Hans Wennborg <hans at chromium.org>
> wrote:
> >> Ping?
> >>
> >> On Fri, Jul 24, 2015 at 9:28 AM, Hans Wennborg <hans at chromium.org>
> wrote:
> >>> Seems reasonable.
> >>>
> >>> Evan, I believe you're the code owner here. OK to merge to 3.7?
> >>>
> >>> On Fri, Jul 24, 2015 at 8:57 AM, Robinson, Paul
> >>> <Paul_Robinson at playstation.sony.com> wrote:
> >>>> Can we please have this merged to the 3.7 branch?
> >>>> Thanks,
> >>>> --paulr
> >>>>
> >>>>> -----Original Message-----
> >>>>> From: llvm-commits-bounces at cs.uiuc.edu [mailto:llvm-commits-
> >>>>> bounces at cs.uiuc.edu] On Behalf Of Sanjay Patel
> >>>>> Sent: Thursday, July 23, 2015 3:57 PM
> >>>>> To: llvm-commits at cs.uiuc.edu
> >>>>> Subject: [llvm] r243057 - fix crash in machine trace metrics due to
> >>>>> processing dbg_value instructions (PR24199)
> >>>>>
> >>>>> Author: spatel
> >>>>> Date: Thu Jul 23 17:56:53 2015
> >>>>> New Revision: 243057
> >>>>>
> >>>>> URL: http://llvm.org/viewvc/llvm-project?rev=243057&view=rev
> >>>>> Log:
> >>>>> fix crash in machine trace metrics due to processing dbg_value
> >>>>> instructions (PR24199)
> >>>>>
> >>>>> The test in PR24199 ( https://llvm.org/bugs/show_bug.cgi?id=24199 )
> >>>>> crashes because machine
> >>>>> trace metrics was not ignoring dbg_value instructions when
> calculating
> >>>>> data dependencies.
> >>>>>
> >>>>> The machine-combiner pass asks machine trace metrics to calculate an
> >>>>> instruction trace,
> >>>>> does some reassociations, and calls
> >>>>> MachineInstr::eraseFromParentAndMarkDBGValuesForRemoval()
> >>>>> along with MachineTraceMetrics::invalidate(). The dbg_value
> instructions
> >>>>> have their operands
> >>>>> invalidated, but the instructions are not expected to be deleted.
> >>>>>
> >>>>> On a subsequent loop iteration of the machine-combiner pass, machine
> trace
> >>>>> metrics would be
> >>>>> called again and die while accessing the invalid debug instructions.
> >>>>>
> >>>>> Differential Revision: http://reviews.llvm.org/D11423