s390: Fixed error in calculating the power of 2 in Int64Mul

src/compiler/s390/instruction-selector-s390.cc

Index: src/compiler/s390/instruction-selector-s390.cc
diff --git a/src/compiler/s390/instruction-selector-s390.cc b/src/compiler/s390/instruction-selector-s390.cc
index 80c6fd048f07319a9f62400428a746d740a15265..f1aa332a493ce44e0fc8aaa4d9598ec3cc8e26b6 100644
--- a/src/compiler/s390/instruction-selector-s390.cc
+++ b/src/compiler/s390/instruction-selector-s390.cc
@@ -1104,7 +1104,7 @@ void InstructionSelector::VisitInt64Mul(Node* node) {
   Node* right = m.right().node();
   if (g.CanBeImmediate(right, kInt32Imm) &&
       base::bits::IsPowerOfTwo64(g.GetImmediate(right))) {
-    int power = 31 - base::bits::CountLeadingZeros64(g.GetImmediate(right));
+    int power = 63 - base::bits::CountLeadingZeros64(g.GetImmediate(right));
     Emit(kS390_ShiftLeft64, g.DefineSameAsFirst(node), g.UseRegister(left),
          g.UseImmediate(power));
     return;