I'm trying to figure out why kwin is (ab)using 100% CPU with the latest r600g git, http://www.phoronix.com/forums/showthread.php?t=26196

Howveer, Valgrind just crashes with:

vex amd64->IR: unhandled instruction bytes: 0xF3 0xF 0xB8 0x4 0x11 0x48

Full story is:

Code:
==20151== Memcheck, a memory error detector
==20151== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
==20151== Using Valgrind-3.5.0 and LibVEX; rerun with -h for copyright info
==20151== Command: kwin --replace
==20151==
kwin(20151) Kephal::DesktopWidgetScreens::DesktopWidgetScreens: foo
kwin(20151) KDecorationPlugins::loadPlugin: kwin : path  "/usr/lib64/kde4/kwin3_kde2.so"  for  "kwin3_kde2"
vex amd64->IR: unhandled instruction bytes: 0xF3 0xF 0xB8 0x4 0x11 0x48
==20151== valgrind: Unrecognised instruction at address 0x102b4628.
==20151== Your program just tried to execute an instruction that Valgrind
==20151== did not recognise.  There are two possible reasons for this.
==20151== 1. Your program has a bug and erroneously jumped to a non-code
==20151==    location.  If you are running Memcheck and you just saw a
==20151==    warning about a bad jump, it's probably your program's fault.
==20151== 2. The instruction is legitimate but Valgrind doesn't handle it,
==20151==    i.e. it's Valgrind's fault.  If you think this is the case or
==20151==    you are not sure, please let us know and we'll try to fix it.
==20151== Either way, Valgrind will now raise a SIGILL signal which will
==20151== probably kill your program.
Application::crashHandler() called with signal 4; recent crashes: 1
KCrash: Application 'kwin' crashing...
KCrash: Attempting to start /usr/lib64/kde4/libexec/drkonqi from kdeinit
sock_file=/home/oyvinds/.kde4/socket-rodan/kdeinit4__0
X Error: BadWindow (invalid Window parameter) 3
  Major opcode: 20 (X_GetProperty)
  Resource id:  0x180011d
kwin(20156) Kephal::DesktopWidgetScreens::DesktopWidgetScreens: foo
kwin(20156) KDecorationPlugins::loadPlugin: kwin : path  "/usr/lib64/kde4/kwin3_kde2.so"  for  "kwin3_kde2"
kwin(20156) KWin::Extensions::init: Extensions: shape: 0x "11"  composite: 0x "4"  render: 0x "b"  fixes: 0x "40"
kwin(20156) KWin::Workspace::setupCompositing: Compositing is turned off in options or disabled
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, ASN: 717016
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, final: 'ID: 29365158 ;WMCLASS: "plasma" : "plasma" ;Caption: "plasma-desktop" ' : 717016
kwin(20156) KWin::Workspace::allowClientActivation: Activation: No client active, allowing
kwin(20156) KWin::Workspace::updateClientArea: screens:  1 desktops:  9
kwin(20156) KWin::Workspace::updateClientArea: Done.
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, ASN: 152041
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, final: 'ID: 96469089 ;WMCLASS: "gnu icecat" : "navigator" ;Caption: "GNU IceCat" ' : 152041
kwin(20156) KWin::Workspace::updateClientArea: screens:  1 desktops:  9
kwin(20156) KWin::Workspace::updateClientArea: Done.
kwin(20156) KWin::Workspace::createTile: Now tiling  "GNU IceCat"
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, ASN: 389913
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, final: 'ID: 100663350 ;WMCLASS: "systemsettings" : "systemsettings" ;Caption: "Skrivebordseffekter ? Systeminnstillinger" ' : 389913
kwin(20156) KWin::Workspace::allowClientActivation: Activation: No client active, allowing
kwin(20156) KWin::Workspace::updateClientArea: screens:  1 desktops:  9
kwin(20156) KWin::Workspace::updateClientArea: Done.
kwin(20156) KWin::Workspace::createTile: Now tiling  "Skrivebordseffekter ? Systeminnstillinger"
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, ASN: 4294967295
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, final: 'ID: 71303172 ;WMCLASS: "xterm" : "mrxvt" ;Caption: "mrxvt" ' : 18446744073709551615
kwin(20156) KWin::Workspace::allowClientActivation: Activation: No client active, allowing
kwin(20156) KWin::Workspace::updateClientArea: screens:  1 desktops:  9
kwin(20156) KWin::Workspace::updateClientArea: Done.
kwin(20156) KWin::Workspace::createTile: Now tiling  "mrxvt"
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, ASN: 716408
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, final: 'ID: 94371938 ;WMCLASS: "gnu icecat" : "navigator" ;Caption: "General Discussion - Phoronix Forums - GNU IceCat" ' : 716408
kwin(20156) KWin::Workspace::updateClientArea: screens:  1 desktops:  9
kwin(20156) KWin::Workspace::updateClientArea: Done.
kwin(20156) KWin::Workspace::createTile: Now tiling  "General Discussion - Phoronix Forums - GNU IceCat"
kwin(20156) KWin::Workspace::updateClientArea: screens:  1 desktops:  9
kwin(20156) KWin::Workspace::updateClientArea: Done.
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, ASN: 4294967295
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, final: 'ID: 102760493 ;WMCLASS: "drkonqi" : "drkonqi" ;Caption: "KWin ? KDE Krasjhåndterer" ' : 757658
kwin(20156) KWin::Workspace::allowClientActivation: Activation, compared: 'ID: 102760493 ;WMCLASS: "drkonqi" : "drkonqi" ;Caption: "KWin ? KDE Krasjhåndterer" ' : 757658 : 757522 : true
kwin(20156) KWin::Workspace::updateClientArea: screens:  1 desktops:  9
kwin(20156) KWin::Workspace::updateClientArea: Done.
kwin(20156) KWin::Workspace::createTile: Now tiling  "KWin ? KDE Krasjhåndterer"
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, ASN: 826115
kwin(20156) KWin::Client::readUserTimeMapTimestamp: User timestamp, final: 'ID: 94427407 ;WMCLASS: "gnu icecat" : "dialog" ;Caption: "" ' : 826115
kwin(20156) KWin::Workspace::allowClientActivation: Activation: Belongs to active application
kwin(20156) KWin::Workspace::updateClientArea: screens:  1 desktops:  9
kwin(20156) KWin::Workspace::updateClientArea: Done.
kwin(20156) KWin::Workspace::createTile: Now tiling  ""
kwin(20156) KWin::Workspace::updateClientArea: screens:  1 desktops:  9
kwin(20156) KWin::Workspace::updateClientArea: Done.
kwin(20156) KWin::Workspace::updateClientArea: screens:  1 desktops:  9
kwin(20156) KWin::Workspace::updateClientArea: Done.
==20151== Invalid free() / delete / delete[]
==20151==    at 0x4C256AD: free (vg_replace_malloc.c:325)
==20151==    by 0x524221A: ??? (in /lib64/libc-2.11.2.so)
==20151==    by 0x5241DB1: ??? (in /lib64/libc-2.11.2.so)
==20151==    by 0x4A205CC: _vgnU_freeres (vg_preloaded.c:62)
==20151==    by 0x574D5F7: ??? (in /usr/lib64/libkdeui.so.5.5.0)
==20151==    by 0x574D6FD: ??? (in /usr/lib64/libkdeui.so.5.5.0)
==20151==    by 0x574DBDA: KCrash::defaultCrashHandler(int) (in /usr/lib64/libkdeui.so.5.5.0)
==20151==    by 0x516B22F: ??? (in /lib64/libc-2.11.2.so)
==20151==    by 0x102B4627: FcCharSetCount (in /usr/lib64/libfontconfig.so.1.4.4)
==20151==    by 0x102BCFBC: FcFontSetList (in /usr/lib64/libfontconfig.so.1.4.4)
==20151==    by 0x102BD7C4: FcFontList (in /usr/lib64/libfontconfig.so.1.4.4)
==20151==    by 0x84FD06B: ??? (in /usr/lib64/qt4/libQtGui.so.4.6.3)
==20151==  Address 0x4067fa0 is not stack'd, malloc'd or (recently) free'd
==20151==
==20151==
==20151== HEAP SUMMARY:
==20151==     in use at exit: 1,124,938 bytes in 16,200 blocks
==20151==   total heap usage: 83,774 allocs, 67,575 frees, 34,101,963 bytes allocated
==20151==
==20151== LEAK SUMMARY:
==20151==    definitely lost: 0 bytes in 0 blocks
==20151==    indirectly lost: 0 bytes in 0 blocks
==20151==      possibly lost: 444,118 bytes in 8,373 blocks
==20151==    still reachable: 680,820 bytes in 7,827 blocks
==20151==         suppressed: 0 bytes in 0 blocks
==20151== Rerun with --leak-check=full to see details of leaked memory
==20151==
==20151== For counts of detected and suppressed errors, rerun with: -v
==20151== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 6 from 5)

[1]+  Exit 253                valgrind kwin --replace
What is going on here?