making the default case command line shorter, not add -no-fence-tso

Author: ChunyuLiao

clang/lib/Driver/ToolChains/Arch/RISCV.cpp

@@ -143,11 +143,8 @@ void riscv::getRISCVTargetFeatures(const Driver &D, const llvm::Triple &Triple,
   }
 
   // -mfence-tso is default, unless -mno-fence-tso is specified.
-  if (Args.hasFlag(options::OPT_mfence_tso, options::OPT_mno_fence_tso, true)) {
-    Features.push_back("-no-fence-tso");
-  } else {
+  if (Args.hasFlag(options::OPT_mno_fence_tso, options::OPT_mfence_tso, false))
     Features.push_back("+no-fence-tso");
-  }
 
   // If -mstrict-align, -mno-strict-align, -mscalar-strict-align, or
   // -mno-scalar-strict-align is passed, use it. Otherwise, the

clang/test/Driver/riscv-features.c

@@ -32,9 +32,9 @@
 // RUN: %clang --target=riscv32-unknown-elf -### %s -mfence-tso 2>&1 | FileCheck %s -check-prefix=FENCE-TSO
 // RUN: %clang --target=riscv32-unknown-elf -### %s -mno-fence-tso 2>&1 | FileCheck %s -check-prefix=NO-FENCE-TSO
 
-// FENCE-TSO: "-target-feature" "-no-fence-tso"
+// FENCE-TSO-NOT: "-target-feature" "-no-fence-tso"
 // NO-FENCE-TSO: "-target-feature" "+no-fence-tso"
-// DEFAULT: "-target-feature" "-no-fence-tso"
+// DEFAULT-NOT: "-target-feature" "-no-fence-tso"
 // DEFAULT-NOT: "-target-feature" "+no-fence-tso"
 
 // RUN: %clang --target=riscv32-unknown-elf -### %s -mno-strict-align 2>&1 | FileCheck %s -check-prefixes=FAST-SCALAR-UNALIGNED-ACCESS,FAST-VECTOR-UNALIGNED-ACCESS