added half2 support

Change-Id: I0f3b9b7037fed97e80ec99f5369c75a63f001aae

src/hip_fp16.cpp

@@ -22,6 +22,7 @@ THE SOFTWARE.
 
 #include"hip/hip_fp16.h"
 
+#if __CLANG_VERSION__ == 35
 
 static const unsigned sign_val = 0x8000;
 static const __half __half_value_one_float = {0x3C00};
@@ -373,4 +374,4 @@ __device__ __half2 __lowhigh2highlow(const __half2 a){
 __device__ __half2 __low2half2(const __half2 a, const __half2 b){
   return {a.q, b.q};
 }
-
+#endif

src/hip_ir.ll

@@ -54,4 +54,9 @@ define linkonce_odr spir_func half @__hip_hsub_gfx803(half %a, half %b) #1 {
   ret half %val
 }
 
+define linkonce_odr spir_func i32 @__hip_hadd2_gfx803(i32 %a i32 %b) #1 {
+  %val = tail call i32 asm "v_add_f16_sdwa $0, $1, $2 dst_sel:WORD_0 dst_unused:UNUSED_PRESERVE src0_sel:WORD_0 src1_sel:WORD_0","=v,v,v"(i32 %a, i32 %b)
+  ret i32 %val
+}
+
 attributes #1 = { alwaysinline nounwind }