libclc: Move rsqrt implementation to a .cl file

[jvesely]

This will be used in a follow-up patch to specialize r600.

[awatry]

Looks good to me.

libclc/generic/include/clc/math/rsqrt.h

-#define rsqrt(x) (1.f/sqrt(x))
+#define __CLC_BODY <clc/math/unary_decl.inc>
+#define __CLC_FUNCTION rsqrt
+
+#include <clc/math/gentype.inc>
+
+#undef __CLC_BODY
+#undef __CLC_FUNCTION

libclc/generic/lib/SOURCES

 math/clc_remainder.cl
 math/remainder.cl
 math/clc_remquo.cl
 math/remquo.cl
 math/rint.cl
 math/clc_rootn.cl
 math/rootn.cl
 math/round.cl
+math/rsqrt.cl
 math/sin.cl
 math/sincos.cl
 math/sincos_helpers.cl
 math/sinh.cl
 math/sinpi.cl
 math/clc_sqrt.cl
 math/sqrt.cl
 math/clc_tan.cl

libclc/generic/lib/math/rsqrt.cl

+#include <clc/clc.h>
+
+#include "../clcmacro.h"
+
+_CLC_OVERLOAD _CLC_DEF float rsqrt(float x)
+{
+    return 1.0f / sqrt(x);
+}
+
+_CLC_UNARY_VECTORIZE(_CLC_OVERLOAD _CLC_DEF, float, rsqrt, float);
+
+#ifdef cl_khr_fp64
+
+#pragma OPENCL EXTENSION cl_khr_fp64 : enable
+
+_CLC_OVERLOAD _CLC_DEF double rsqrt(double x)
+{
+    return 1.0 / sqrt(x);
+}
+
+_CLC_UNARY_VECTORIZE(_CLC_OVERLOAD _CLC_DEF, double, rsqrt, double);
+
+#endif