diff --git a/valgrind-3.8.0-lzcnt-tzcnt-bugfix.patch b/valgrind-3.8.0-lzcnt-tzcnt-bugfix.patch
new file mode 100644
index 0000000..00d8bf3
--- /dev/null
+++ b/valgrind-3.8.0-lzcnt-tzcnt-bugfix.patch
@@ -0,0 +1,66 @@
+------------------------------------------------------------------------
+r2478 | sewardj | 2012-08-23 22:14:51 +0200 (Thu, 23 Aug 2012) | 4 lines
+
+Fix LZCNT and TZCNT properly.  Fixes #295808.  (Jakub Jelinek,
+jakub@redhat.com)
+
+
+------------------------------------------------------------------------
+Index: priv/guest_amd64_toIR.c
+===================================================================
+--- valgrind-3.8.0/VEX/priv/guest_amd64_toIR.c	(revision 2477)
++++ valgrind-3.8.0/VEX/priv/guest_amd64_toIR.c	(revision 2478)
+@@ -20084,13 +20084,16 @@
+       return delta;
+ 
+    case 0xBC: /* BSF Gv,Ev */
+-      if (haveF2orF3(pfx)) goto decode_failure;
++      if (haveF2(pfx)) goto decode_failure;
+       delta = dis_bs_E_G ( vbi, pfx, sz, delta, True );
+       return delta;
+ 
+    case 0xBD: /* BSR Gv,Ev */
+-      if (!haveF2orF3(pfx)) {
+-         /* no-F2 no-F3 0F BD = BSR */
++      if (!haveF2orF3(pfx)
++          || (haveF3noF2(pfx)
++              && 0 == (archinfo->hwcaps & VEX_HWCAPS_AMD64_LZCNT))) {
++         /* no-F2 no-F3 0F BD = BSR
++                  or F3 0F BD = REP; BSR on older CPUs.  */
+          delta = dis_bs_E_G ( vbi, pfx, sz, delta, False );
+          return delta;
+       }
+Index: priv/guest_x86_toIR.c
+===================================================================
+--- valgrind-3.8.0/VEX/priv/guest_x86_toIR.c	(revision 2477)
++++ valgrind-3.8.0/VEX/priv/guest_x86_toIR.c	(revision 2478)
+@@ -14021,12 +14021,28 @@
+       for the rest, it means REP) */
+    case 0xF3: { 
+       Addr32 eip_orig = guest_EIP_bbstart + delta_start;
+-      if (sorb != 0) goto decode_failure;
+       abyte = getIByte(delta); delta++;
+ 
+       if (abyte == 0x66) { sz = 2; abyte = getIByte(delta); delta++; }
+ 
++      if (sorb != 0 && abyte != 0x0F) goto decode_failure;
++
+       switch (abyte) {
++      case 0x0F:
++         switch (getIByte(delta)) {
++         /* On older CPUs, TZCNT behaves the same as BSF.  */
++         case 0xBC: /* REP BSF Gv,Ev */
++            delta = dis_bs_E_G ( sorb, sz, delta + 1, True );
++            break;
++         /* On older CPUs, LZCNT behaves the same as BSR.  */
++         case 0xBD: /* REP BSR Gv,Ev */
++            delta = dis_bs_E_G ( sorb, sz, delta + 1, False );
++            break;
++         default:
++            goto decode_failure;
++         }
++         break;
++
+       case 0xA4: sz = 1;   /* REP MOVS<sz> */
+       case 0xA5:
+          dis_REP_op ( &dres, X86CondAlways, dis_MOVS, sz, eip_orig, 
diff --git a/valgrind.spec b/valgrind.spec
index e7a9051..47a87a4 100644
--- a/valgrind.spec
+++ b/valgrind.spec
@@ -21,6 +21,7 @@ Patch10: valgrind-3.8.0-ldso-supp.patch
 Patch11: valgrind-3.8.0-x86-backtrace.patch
 Patch12: valgrind-3.8.0-find-buildid.patch
 Patch13: valgrind-3.8.0-abbrev-parsing.patch
+Patch14: valgrind-3.8.0-lzcnt-tzcnt-bugfix.patch
 
 Obsoletes: valgrind-callgrind
 %ifarch x86_64 ppc64
@@ -113,6 +114,7 @@ for details.
 %patch11 -p1
 %patch12 -p1
 %patch13 -p1
+%patch14 -p1
 
 %build
 CC=gcc
@@ -223,6 +225,9 @@ echo ===============END TESTING===============
 %endif
 
 %changelog
+* Tue Sep 11 2012 Mark Wielaard <mjw@redhat.com>
+- Add valgrind-3.8.0-lzcnt-tzcnt-bugfix.patch (KDE#295808)
+
 * Mon Aug 27 2012 Mark Wielaard <mjw@redhat.com> 3.8.0-5
 - Add valgrind-3.8.0-abbrev-parsing.patch for #849783 (KDE#305513).