Two days old build breakage on i386.

[Johan Tibell]

I'm trying to understand the output from the register allocator:

  (GHC version 7.9.20140626 for i386-unknown-linux):
RegAllocLinear.allocRegsAndSpill: no spill candidates

    allocating vreg:  VirtualRegI n1nD
    assignment:       [(n1nD,InMem 0),(n1nE,InReg (RealRegSingle
2)),(n1nF,InReg (RealRegSingle 3))]
    freeRegs:         FreeRegs 4282318848
    initFreeRegs:     FreeRegs 4282318861

Without understanding exactly what's wrong, the message above suggests that
we're trying to allocate a reg for n1nD, but there's already an assignment
for that virtual reg, is that right?



On Thu, Jun 26, 2014 at 3:05 PM, Johan Tibell <johan.tibell at gmail.com>
wrote:

> Herbert pushed my revert for me a minute ago. Everyone should be good once
> they sync.
>
>
> On Thu, Jun 26, 2014 at 2:51 PM, Johan Tibell <johan.tibell at gmail.com>
> wrote:
>
>> I guess you don't have 04dd7cb3423f1940242fdfe2ea2e3b8abd68a177 (which I
>> pushed this morning) which is fine. You should be in a good state now when
>> d8abf85f8ca176854e9d5d0b12371c4bc402aac3 is reverted.
>>
>>
>> On Thu, Jun 26, 2014 at 2:49 PM, Simon Peyton Jones <
>> simonpj at microsoft.com> wrote:
>>
>>>  git revert d8abf85f8ca176854e9d5d0b12371c4bc402aac3
>>>
>>> [master f958079] Revert "Add more primops for atomic ops on byte arrays"
>>>
>>> 23 files changed, 86 insertions(+), 1016 deletions(-)
>>>
>>> rewrite compiler/nativeGen/CPrim.hs (62%)
>>>
>>> delete mode 100644 libraries/ghc-prim/cbits/atomic.c
>>>
>>> delete mode 100644 testsuite/tests/concurrent/should_run/AtomicPrimops.hs
>>>
>>> delete mode 100644
>>> testsuite/tests/concurrent/should_run/AtomicPrimops.stdout
>>>
>>> HEAD $ git revert 04dd7cb3423f1940242fdfe2ea2e3b8abd68a177
>>>
>>> fatal: bad object 04dd7cb3423f1940242fdfe2ea2e3b8abd68a177
>>>
>>> HEAD $
>>>
>>> What now?
>>>
>>> Simon
>>>
>>>
>>>
>>> *From:* Johan Tibell [mailto:johan.tibell at gmail.com]
>>> *Sent:* 26 June 2014 13:25
>>> *To:* Simon Peyton Jones
>>> *Cc:* Karel Gardas; ghc-devs
>>> *Subject:* Re: Two days old build breakage on i386.
>>>
>>>
>>>
>>> Just to make sure this is the same breakage, are you on an i386 Windows
>>> machine? If so git revert d8abf85f8ca176854e9d5d0b12371c4bc402aac3
>>> and 04dd7cb3423f1940242fdfe2ea2e3b8abd68a177 to get unstuck.
>>>
>>>
>>>
>>> On Thu, Jun 26, 2014 at 2:13 PM, Simon Peyton Jones <
>>> simonpj at microsoft.com> wrote:
>>>
>>>  Aaaargh!  Once again the Windows build is broken.  I am utterly stalled.
>>>
>>> Moreover -fregs-graph and -fregs-iterative now *silently* do nothing.
>>>  At least they should elicit warnings saying that they are disabled pending
>>> the fix to X and Y.
>>>
>>> Please can someone bisect to find out which patch is the culprit?
>>>
>>> I wish we had a more systematic way to find this out. I hate being the
>>> main person who gets stuck because some unrelated change has broken the
>>> Windows build.  (Thanks for Karel, who got to it a day before me.)
>>>
>>> Thanks
>>>
>>> Simon
>>>
>>>
>>> | -----Original Message-----
>>> | From: ghc-devs [mailto:ghc-devs-bounces at haskell.org] On Behalf Of
>>> Karel
>>> | Gardas
>>> | Sent: 26 June 2014 09:56
>>> | To: ghc-devs; Johan Tibell
>>> | Subject: Two days old build breakage on i386.
>>> |
>>> |
>>> | Hello,
>>> |
>>> | builders running on i386 building for this platform caught issue which
>>> | shows as a build breakage:
>>> |
>>> | ghc-stage1: panic! (the 'impossible' happened)
>>> | (GHC version 7.9.20140624 for i386-unknown-linux):
>>> | RegAllocLinear.allocRegsAndSpill: no spill candidates
>>> | allocating vreg: VirtualRegI n1Q6
>>> | assignment: [(c1PV,InMem 2),(n1Q5,InBoth (RealRegSingle 3)
>>> | 0),(n1Q6,InMem 1),(n1Q7,InMem 3),(n1Q9,InReg (RealRegSingle 2))]
>>> | freeRegs: FreeRegs 4282318848
>>> | initFreeRegs: FreeRegs 4282318861
>>> | Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
>>> | make[1]: ***
>>> | [libraries/ghc-prim/dist-install/build/GHC/PrimopWrappers.o] Error 1
>>> | libraries/ghc-prim/ghc.mk:4: recipe for target
>>> | 'libraries/ghc-prim/dist-install/build/GHC/PrimopWrappers.o' failed
>>> |
>>> | Have a look for example on linux-i386 buildot log here:
>>> |
>>> http://haskell.inf.elte.hu/builders/validator1-linux-x86-head/18/7.html
>>> |
>>> | Anyway, this happens on Linux, FreeBSD and Solaris buildbots on i386 so
>>> | it's OS independent and probably 32bit/i386 platform specific and it's
>>> | two days old breakage now. The last two night builds fail on all
>>> | mentioned buildbots. I'm not sure but perhaps:
>>> |
>>> | commit d8abf85f8ca176854e9d5d0b12371c4bc402aac3
>>> | Author: Johan Tibell <johan.tibell at gmail.com>
>>> | Date:   Mon Jun 9 11:43:21 2014 +0200
>>> |
>>> | triggers that issue? I'm not claiming that the commit is actual
>>> culprit,
>>> | this may be just recently un-hidden issue in linear regs allocator on
>>> | i386!
>>> |
>>> | Thanks!
>>> | Karel
>>>
>>> | _______________________________________________
>>> | ghc-devs mailing list
>>> | ghc-devs at haskell.org
>>> | http://www.haskell.org/mailman/listinfo/ghc-devs
>>>
>>>
>>>
>>
>>
>
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