msvcrt: Use the atan() implementation from the bundled musl library.

dlls/msvcrt/math.c

@@ -78,11 +78,13 @@ void msvcrt_init_math( void *module )
 }
 
 /* Copied from musl: src/internal/libm.h */
+#if !defined(__i386__) || _MSVCR_VER>=120
 static inline float fp_barrierf(float x)
 {
     volatile float y = x;
     return y;
 }
+#endif
 
 static inline double fp_barrier(double x)
 {
@@ -489,93 +491,14 @@ double CDECL MSVCRT_asin( double x )
 
 /*********************************************************************
  *		atan (MSVCRT.@)
- *
- * Copied from musl: src/math/atan.c
- */
-double CDECL atan( double x )
-{
-    static const double atanhi[] = {
-        4.63647609000806093515e-01,
-        7.85398163397448278999e-01,
-        9.82793723247329054082e-01,
-        1.57079632679489655800e+00,
-    };
-    static const double atanlo[] = {
-        2.26987774529616870924e-17,
-        3.06161699786838301793e-17,
-        1.39033110312309984516e-17,
-        6.12323399573676603587e-17,
-    };
-    static const double aT[] = {
-        3.33333333333329318027e-01,
-        -1.99999999998764832476e-01,
-        1.42857142725034663711e-01,
-        -1.11111104054623557880e-01,
-        9.09088713343650656196e-02,
-        -7.69187620504482999495e-02,
-        6.66107313738753120669e-02,
-        -5.83357013379057348645e-02,
-        4.97687799461593236017e-02,
-        -3.65315727442169155270e-02,
-        1.62858201153657823623e-02,
-    };
-
-    double w, s1, s2, z;
-    unsigned int ix, sign;
-    int id;
-
-#if _MSVCR_VER == 0
+ */
+#if _MSVCR_VER == 0  /* other versions call atan() directly */
+double CDECL MSVCRT_atan( double x )
+{
     if (isnan(x)) return math_error(_DOMAIN, "atan", x, 0, x);
-#endif
-
-    ix = *(ULONGLONG*)&x >> 32;
-    sign = ix >> 31;
-    ix &= 0x7fffffff;
-    if (ix >= 0x44100000) {   /* if |x| >= 2^66 */
-        if (isnan(x))
-            return x;
-        z = atanhi[3] + 7.5231638452626401e-37;
-        return sign ? -z : z;
-    }
-    if (ix < 0x3fdc0000) {    /* |x| < 0.4375 */
-        if (ix < 0x3e400000) {  /* |x| < 2^-27 */
-            if (ix < 0x00100000)
-                /* raise underflow for subnormal x */
-                fp_barrierf((float)x);
-            return x;
-        }
-        id = -1;
-    } else {
-        x = fabs(x);
-        if (ix < 0x3ff30000) {  /* |x| < 1.1875 */
-            if (ix < 0x3fe60000) {  /*  7/16 <= |x| < 11/16 */
-                id = 0;
-                x = (2.0 * x - 1.0) / (2.0 + x);
-            } else {                /* 11/16 <= |x| < 19/16 */
-                id = 1;
-                x = (x - 1.0) / (x + 1.0);
-            }
-        } else {
-            if (ix < 0x40038000) {  /* |x| < 2.4375 */
-                id = 2;
-                x = (x - 1.5) / (1.0 + 1.5 * x);
-            } else {                /* 2.4375 <= |x| < 2^66 */
-                id = 3;
-                x = -1.0 / x;
-            }
-        }
-    }
-    /* end of argument reduction */
-    z = x * x;
-    w = z * z;
-    /* break sum from i=0 to 10 aT[i]z**(i+1) into odd and even poly */
-    s1 = z * (aT[0] + w * (aT[2] + w * (aT[4] + w * (aT[6] + w * (aT[8] + w * aT[10])))));
-    s2 = w * (aT[1] + w * (aT[3] + w * (aT[5] + w * (aT[7] + w * aT[9]))));
-    if (id < 0)
-        return x - x * (s1 + s2);
-    z = atanhi[id] - (x * (s1 + s2) - atanlo[id] - x);
-    return sign ? -z : z;
+    return atan( x );
 }
+#endif
 
 /*********************************************************************
  *		exp (MSVCRT.@)

dlls/msvcrt/msvcrt.spec

@@ -1254,7 +1254,7 @@
 @ cdecl asctime(ptr)
 @ cdecl asctime_s(ptr long ptr)
 @ cdecl asin(double) MSVCRT_asin
-@ cdecl atan(double)
+@ cdecl atan(double) MSVCRT_atan
 @ cdecl atan2(double double)
 @ cdecl -arch=!i386 asinf(float)
 @ cdecl -arch=!i386 atanf(float) MSVCRT_atanf