[RVV] Fix compile warning in row_rvv

1. Fix compile warning in row_rvv.cc

2. Avoid compile row_rvv.cc/scale_rvv.cc when using GCC
There is no RVV segment load & store on GCC.
Hence, avoid compiling rvv code on GCC temporarily.

3. Add several compile options to cmake build flow
  -Wno-sign-compare
  -Wno-unused-function
  -Wunused-variable
  -Wuninitialized

Bug: libyuv:956
Change-Id: I9577f98190fc9b28fb6fde65d82d0c67ce54f9ee
Signed-off-by: Bruce Lai <bruce.lai@sifive.com>
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/4615441
Commit-Queue: Frank Barchard <fbarchard@chromium.org>
Reviewed-by: Frank Barchard <fbarchard@chromium.org>

3 files changed, 36 insertions, 32 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7a4a1994..6f372949 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -29,6 +29,12 @@ endif()
 # this creates the static library (.a)
 ADD_LIBRARY				( ${ly_lib_static} STATIC ${ly_source_files} )
 
+target_compile_options(${ly_lib_static} PRIVATE
+  -Wno-sign-compare
+  -Wno-unused-function
+  -Wunused-variable
+  -Wuninitialized)
+
 # this creates the shared library (.so)
 ADD_LIBRARY				( ${ly_lib_shared} SHARED ${ly_source_files} )
 SET_TARGET_PROPERTIES	( ${ly_lib_shared} PROPERTIES OUTPUT_NAME "${ly_lib_name}" )
diff --git a/source/row_rvv.cc b/source/row_rvv.cc
index a79560c7..29422574 100644
--- a/source/row_rvv.cc
+++ b/source/row_rvv.cc
@@ -17,7 +17,8 @@
 
 #include "libyuv/row.h"
 
-#if !defined(LIBYUV_DISABLE_RVV) && defined(__riscv_vector)
+// This module is for clang rvv. GCC hasn't supported segment load & store.
+#if !defined(LIBYUV_DISABLE_RVV) && defined(__riscv_vector) && defined(__clang__)
 #include <assert.h>
 #include <riscv_vector.h>
 
@@ -29,17 +30,17 @@ extern "C" {
 // Fill YUV -> RGB conversion constants into vectors
 // NOTE: To match behavior on other platforms, vxrm (fixed-point rounding mode
 // register) is set to round-to-nearest-up mode(0).
-#define YUVTORGB_SETUP(vl, yuvconst, ub, vr, ug, vg, yg, bb, bg, br) \
-  {                                                                  \
-    asm volatile("csrwi vxrm, 0");                                   \
-    ub = yuvconst->kUVCoeff[0];                                      \
-    vr = yuvconst->kUVCoeff[1];                                      \
-    ug = yuvconst->kUVCoeff[2];                                      \
-    vg = yuvconst->kUVCoeff[3];                                      \
-    yg = yuvconst->kRGBCoeffBias[0];                                 \
-    bb = yuvconst->kRGBCoeffBias[1] + 32;                            \
-    bg = yuvconst->kRGBCoeffBias[2] - 32;                            \
-    br = yuvconst->kRGBCoeffBias[3] + 32;                            \
+#define YUVTORGB_SETUP(yuvconst, ub, vr, ug, vg, yg, bb, bg, br) \
+  {                                                              \
+    asm volatile("csrwi vxrm, 0");                               \
+    ub = yuvconst->kUVCoeff[0];                                  \
+    vr = yuvconst->kUVCoeff[1];                                  \
+    ug = yuvconst->kUVCoeff[2];                                  \
+    vg = yuvconst->kUVCoeff[3];                                  \
+    yg = yuvconst->kRGBCoeffBias[0];                             \
+    bb = yuvconst->kRGBCoeffBias[1] + 32;                        \
+    bg = yuvconst->kRGBCoeffBias[2] - 32;                        \
+    br = yuvconst->kRGBCoeffBias[3] + 32;                        \
   }
 
 // Read [VLEN/8] Y, [VLEN/(8 * 2)] U and [VLEN/(8 * 2)] V from 422
@@ -266,14 +267,14 @@ void I444ToARGBRow_RVV(const uint8_t* src_y,
                        uint8_t* dst_argb,
                        const struct YuvConstants* yuvconstants,
                        int width) {
-  size_t vl;
   size_t w = (size_t)width;
+  size_t vl = __riscv_vsetvl_e8m2(w);
   uint8_t ub, vr, ug, vg;
   int16_t yg, bb, bg, br;
   vuint8m2_t v_u, v_v;
   vuint8m2_t v_b, v_g, v_r, v_a;
   vuint16m4_t v_y_16, v_g_16, v_b_16, v_r_16;
-  YUVTORGB_SETUP(vl, yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
+  YUVTORGB_SETUP(yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
   v_a = __riscv_vmv_v_x_u8m2(255u, vl);
   do {
     READYUV444(vl, v_u, v_v, v_y_16);
@@ -303,7 +304,7 @@ void I444AlphaToARGBRow_RVV(const uint8_t* src_y,
   vuint8m2_t v_u, v_v;
   vuint8m2_t v_b, v_g, v_r, v_a;
   vuint16m4_t v_y_16, v_g_16, v_b_16, v_r_16;
-  YUVTORGB_SETUP(vl, yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
+  YUVTORGB_SETUP(yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
   do {
     READYUV444(vl, v_u, v_v, v_y_16);
     v_a = __riscv_vle8_v_u8m2(src_a, vl);
@@ -333,7 +334,7 @@ void I444ToRGB24Row_RVV(const uint8_t* src_y,
   vuint8m2_t v_u, v_v;
   vuint8m2_t v_b, v_g, v_r;
   vuint16m4_t v_y_16, v_g_16, v_b_16, v_r_16;
-  YUVTORGB_SETUP(vl, yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
+  YUVTORGB_SETUP(yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
   do {
     READYUV444(vl, v_u, v_v, v_y_16);
     YUVTORGB(vl, v_u, v_v, ub, vr, ug, vg, yg, bb, bg, br, v_y_16, v_g_16,
@@ -354,14 +355,14 @@ void I422ToARGBRow_RVV(const uint8_t* src_y,
                        uint8_t* dst_argb,
                        const struct YuvConstants* yuvconstants,
                        int width) {
-  size_t vl;
   size_t w = (size_t)width;
+  size_t vl = __riscv_vsetvl_e8m2(w);
   uint8_t ub, vr, ug, vg;
   int16_t yg, bb, bg, br;
   vuint8m2_t v_u, v_v;
   vuint8m2_t v_b, v_g, v_r, v_a;
   vuint16m4_t v_y_16, v_g_16, v_b_16, v_r_16;
-  YUVTORGB_SETUP(vl, yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
+  YUVTORGB_SETUP(yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
   v_a = __riscv_vmv_v_x_u8m2(255u, vl);
   do {
     READYUV422(vl, v_u, v_v, v_y_16);
@@ -391,7 +392,7 @@ void I422AlphaToARGBRow_RVV(const uint8_t* src_y,
   vuint8m2_t v_u, v_v;
   vuint8m2_t v_b, v_g, v_r, v_a;
   vuint16m4_t v_y_16, v_g_16, v_b_16, v_r_16;
-  YUVTORGB_SETUP(vl, yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
+  YUVTORGB_SETUP(yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
   do {
     READYUV422(vl, v_u, v_v, v_y_16);
     v_a = __riscv_vle8_v_u8m2(src_a, vl);
@@ -414,14 +415,14 @@ void I422ToRGBARow_RVV(const uint8_t* src_y,
                        uint8_t* dst_rgba,
                        const struct YuvConstants* yuvconstants,
                        int width) {
-  size_t vl;
   size_t w = (size_t)width;
+  size_t vl = __riscv_vsetvl_e8m2(w);
   uint8_t ub, vr, ug, vg;
   int16_t yg, bb, bg, br;
   vuint8m2_t v_u, v_v;
   vuint8m2_t v_b, v_g, v_r, v_a;
   vuint16m4_t v_y_16, v_g_16, v_b_16, v_r_16;
-  YUVTORGB_SETUP(vl, yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
+  YUVTORGB_SETUP(yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
   v_a = __riscv_vmv_v_x_u8m2(255u, vl);
   do {
     READYUV422(vl, v_u, v_v, v_y_16);
@@ -450,7 +451,7 @@ void I422ToRGB24Row_RVV(const uint8_t* src_y,
   vuint8m2_t v_u, v_v;
   vuint8m2_t v_b, v_g, v_r;
   vuint16m4_t v_y_16, v_g_16, v_b_16, v_r_16;
-  YUVTORGB_SETUP(vl, yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
+  YUVTORGB_SETUP(yuvconstants, ub, vr, ug, vg, yg, bb, bg, br);
   do {
     READYUV422(vl, v_u, v_v, v_y_16);
     YUVTORGB(vl, v_u, v_v, ub, vr, ug, vg, yg, bb, bg, br, v_y_16, v_g_16,
@@ -982,4 +983,4 @@ void ARGBCopyYToAlphaRow_RVV(const uint8_t* src, uint8_t* dst, int width) {
 }  // namespace libyuv
 #endif
 
-#endif  // !defined(LIBYUV_DISABLE_RVV) && defined(__riscv_vector)
+#endif  // !defined(LIBYUV_DISABLE_RVV) && defined(__riscv_vector) && defined(__clang__)
diff --git a/source/scale_rvv.cc b/source/scale_rvv.cc
index 749deccd..137da77e 100644
--- a/source/scale_rvv.cc
+++ b/source/scale_rvv.cc
@@ -18,8 +18,8 @@
 #include "libyuv/row.h"
 #include "libyuv/scale_row.h"
 
-// This module is for gcc/clang rvv.
-#if !defined(LIBYUV_DISABLE_RVV) && defined(__riscv_vector)
+// This module is for clang rvv. GCC hasn't supported segment load & store.
+#if !defined(LIBYUV_DISABLE_RVV) && defined(__riscv_vector) && defined(__clang__)
 #include <riscv_vector.h>
 
 #ifdef __cplusplus
@@ -51,11 +51,9 @@ void ScaleARGBRowDown2_RVV(const uint8_t* src_argb,
   const uint64_t* src = (const uint64_t*)(src_argb);
   uint32_t* dst = (uint32_t*)(dst_argb);
   do {
-    vuint64m8_t v_data;
-    vuint32m4_t v_dst;
     size_t vl = __riscv_vsetvl_e64m8(w);
-    v_data = __riscv_vle64_v_u64m8(src, vl);
-    v_dst = __riscv_vnsrl_wx_u32m4(v_data, 32, vl);
+    vuint64m8_t v_data = __riscv_vle64_v_u64m8(src, vl);
+    vuint32m4_t v_dst = __riscv_vnsrl_wx_u32m4(v_data, 32, vl);
     __riscv_vse32_v_u32m4(dst, v_dst, vl);
     w -= vl;
     src += vl;
@@ -133,9 +131,8 @@ void ScaleARGBRowDownEven_RVV(const uint8_t* src_argb,
   uint32_t* dst = (uint32_t*)(dst_argb);
   const int stride_byte = src_stepx * 4;
   do {
-    vuint32m8_t v_row;
     size_t vl = __riscv_vsetvl_e32m8(w);
-    v_row = __riscv_vlse32_v_u32m8(src, stride_byte, vl);
+    vuint32m8_t v_row = __riscv_vlse32_v_u32m8(src, stride_byte, vl);
     __riscv_vse32_v_u32m8(dst, v_row, vl);
     w -= vl;
     src += vl * src_stepx;
@@ -602,4 +599,4 @@ void ScaleUVRowDownEven_RVV(const uint8_t* src_uv,
 }  // namespace libyuv
 #endif
 
-#endif  // !defined(LIBYUV_DISABLE_RVV) && defined(__riscv_vector)
+#endif  // !defined(LIBYUV_DISABLE_RVV) && defined(__riscv_vector) && defined(__clang__)