Fix bug 343802. We need to handle one more special case in the spechelper


git-svn-id: svn://svn.valgrind.org/vex/trunk@3083 8f6e269a-dfd6-0310-a8e1-e2731360e62c
diff --git a/priv/guest_s390_helpers.c b/priv/guest_s390_helpers.c
index 78ca2ef..df1f24b 100644
--- a/priv/guest_s390_helpers.c
+++ b/priv/guest_s390_helpers.c
@@ -1958,7 +1958,10 @@
             return unop(Iop_1Uto32, binop(Iop_CmpNE64, cc_dep1, mkU64(0)));
          }
          if (cond == 4 || cond == 4 + 1) {
-            return unop(Iop_1Uto32, binop(Iop_CmpLT64S, cc_dep1, mkU64(0)));
+             /* Special case cc_dep < 0. Only check the MSB to avoid bogus
+               memcheck complaints due to gcc magic. Fixes 343802
+             */
+            return unop(Iop_64to32, binop(Iop_Shr64, cc_dep1, mkU8(63)));
          }
          if (cond == 8 + 4 || cond == 8 + 4 + 1) {
             return unop(Iop_1Uto32, binop(Iop_CmpLE64S, cc_dep1, mkU64(0)));