Add signMask getter to Float32x4

runtime/vm/flow_graph_type_propagator.cc

Index: runtime/vm/flow_graph_type_propagator.cc
diff --git a/runtime/vm/flow_graph_type_propagator.cc b/runtime/vm/flow_graph_type_propagator.cc
index 013f7525bf1730d4f5ddd1e9558c0b587bf89ee0..2ea65bac1ed80ee05be97be0de39a4b61f60acc4 100644
--- a/runtime/vm/flow_graph_type_propagator.cc
+++ b/runtime/vm/flow_graph_type_propagator.cc
@@ -1044,6 +1044,11 @@ CompileType Float32x4ShuffleInstr::ComputeType() const {
 }
 
 
+CompileType Simd32x4GetSignMaskInstr::ComputeType() const {
+  return CompileType::Int();
+}
+
+
 CompileType Float32x4ConstructorInstr::ComputeType() const {
   return CompileType::FromCid(kFloat32x4Cid);
 }
@@ -1108,6 +1113,7 @@ CompileType Uint32x4BoolConstructorInstr::ComputeType() const {
   return CompileType::FromCid(kUint32x4Cid);
 }
 
+
 CompileType Uint32x4GetFlagInstr::ComputeType() const {
   return CompileType::FromCid(kBoolCid);
 }