[SYCL][Devicelib] Implement cmath rintf wrapper with __spirv_ocl_rint (#18857)

This PR is to support the use of std::rint in device code. Currently it
is resolved to rintf symbol. With this PR, the rintf symbol is resolved
by libdevice.

Author: wenju-he

libdevice/cmath_wrapper.cpp

@@ -198,16 +198,17 @@ float nearbyintf(float x) { return __nv_nearbyintf(x); }
 extern "C" SYCL_EXTERNAL float __nv_rintf(float);
 DEVICE_EXTERN_C_INLINE
 float rintf(float x) { return __nv_rintf(x); }
-#endif // __NVPTX__
-
-#ifdef __AMDGCN__
+#elif defined(__AMDGCN__)
 extern "C" SYCL_EXTERNAL float __ocml_nearbyint_f32(float);
 DEVICE_EXTERN_C_INLINE
 float nearbyintf(float x) { return __ocml_nearbyint_f32(x); }
 
 extern "C" SYCL_EXTERNAL float __ocml_rint_f32(float);
 DEVICE_EXTERN_C_INLINE
 float rintf(float x) { return __ocml_rint_f32(x); }
-#endif // __AMDGCN__
+#else
+DEVICE_EXTERN_C_INLINE
+float rintf(float x) { return __spirv_ocl_rint(x); }
+#endif
 
 #endif // __SPIR__ || __SPIRV__ || __NVPTX__ || __AMDGCN__

libdevice/cmath_wrapper_fp64.cpp

@@ -188,17 +188,18 @@ double nearbyint(double x) { return __nv_nearbyint(x); }
 extern "C" SYCL_EXTERNAL double __nv_rint(double);
 DEVICE_EXTERN_C_INLINE
 double rint(double x) { return __nv_rint(x); }
-#endif // __NVPTX__
-
-#ifdef __AMDGCN__
+#elif defined(__AMDGCN__)
 extern "C" SYCL_EXTERNAL double __ocml_nearbyint_f64(double);
 DEVICE_EXTERN_C_INLINE
 double nearbyint(double x) { return __ocml_nearbyint_f64(x); }
 
 extern "C" SYCL_EXTERNAL double __ocml_rint_f64(double);
 DEVICE_EXTERN_C_INLINE
 double rint(double x) { return __ocml_rint_f64(x); }
-#endif // __AMDGCN__
+#else
+DEVICE_EXTERN_C_INLINE
+double rint(double x) { return __spirv_ocl_rint(x); }
+#endif
 
 #if defined(_MSC_VER)
 #include <math.h>

libdevice/test/check_cmath.txt

@@ -0,0 +1,12 @@
+REQUIRES: libsycldevice
+
+Check functions in fp32 libdevice spirv file.
+
+RUN: llvm-spirv --spirv-target-env=SPV-IR -r %libsycldevice_spv_dir/libsycl-cmath.spv -o %t.bc
+RUN: llvm-dis %t.bc -o %t.ll
+RUN: FileCheck %s --input-file %t.ll
+
+CHECK: target triple ={{.*}}spir64
+
+CHECK-LABEL: define spir_func float @rintf(
+CHECK: call spir_func float @_Z16__spirv_ocl_rintf(