remove static

Author: Zhang Yan

lib/gc/Transforms/Pipeline.cpp

@@ -56,8 +56,7 @@ void populateVectorPasses(mlir::PassManager &pm) {
   pm.addNestedPass<func::FuncOp>(math::createMathLegalizeToF32());
   // sourceTypeStrs can be extended
   arith::ArithEmulateUnsupportedFloatsOptions options;
-  const static std::string strType = "bf16";
-  options.sourceTypeStrs = {&strType, 1};
+  options.sourceTypeStrs = std::array<std::string, 1>({"bf16"});
   options.targetTypeStr = "f32";
   pm.addNestedPass<func::FuncOp>(
       arith::createArithEmulateUnsupportedFloats(options));