feat(riscv): speed up bazel build and fix rv64gc without rvv build

GitOrigin-RevId: 9bcbb4a9a06e80ea9982256f84c69ed5d312476d

dnn/test/fallback/gi.cpp

@@ -2095,7 +2095,12 @@ TEST_F(FALLBACK, GiXorFloat32) {
 
 TEST_F(FALLBACK, GiBSLFloat32) {
     GI_FLOAT32_t src0, src1, ret, na;
+
+#if defined(GI_RVV_INTRINSICS)
+    vuint32m1_t mask = vundefined_u32m1();
+#else
     GI_UINT32_t mask;
+#endif
     std::vector<float> s0{1.1f, 2.2f, 4.5f, 4.9f};
     std::vector<float> s1{2312.1f, 345.244f, 3.59f, -12.8f};
     std::vector<std::vector<uint32_t>> s2s = {

toolchains/riscv64-linux-gnu.toolchain.cmake

@@ -14,6 +14,9 @@ set(RISCV_TOOLCHAIN_ROOT
 
 set(CMAKE_C_COMPILER "${RISCV_TOOLCHAIN_ROOT}/bin/riscv64-unknown-linux-gnu-gcc")
 set(CMAKE_CXX_COMPILER "${RISCV_TOOLCHAIN_ROOT}/bin/riscv64-unknown-linux-gnu-g++")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -march=rv64gc -mabi=lp64d")
+set(CMAKE_CXX_FLAGS
+    "${CMAKE_CXX_FLAGS} -march=rv64gc -mabi=lp64d -Wno-error=attributes")
 set(CMAKE_FIND_ROOT_PATH "${RISCV_TOOLCHAIN_ROOT}/riscv64-unknown-linux-gnu")
 set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)