Two days old build breakage on i386.

Simon Peyton Jones simonpj at
Thu Jun 26 12:49:24 UTC 2014

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

What now?

From: Johan Tibell [mailto:johan.tibell at]
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<mailto:simonpj at>> 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.)



| -----Original Message-----
| From: ghc-devs [mailto:ghc-devs-bounces at<mailto:ghc-devs-bounces at>] 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:
| make[1]: ***
| [libraries/ghc-prim/dist-install/build/GHC/PrimopWrappers.o] Error 1
| libraries/ghc-prim/<>: recipe for target
| 'libraries/ghc-prim/dist-install/build/GHC/PrimopWrappers.o' failed
| Have a look for example on linux-i386 buildot log here:
| 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<mailto:johan.tibell at>>
| 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<mailto:ghc-devs at>

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