msvcrt: Import erfc implementation from musl.

configure

@@ -19623,7 +19623,6 @@ for ac_func in \
 	atanh \
 	atanhf \
 	erf \
-	erfc \
 	exp2 \
 	exp2f \
 	expm1 \

configure.ac

@@ -2663,7 +2663,6 @@ AC_CHECK_FUNCS(\
 	atanh \
 	atanhf \
 	erf \
-	erfc \
 	exp2 \
 	exp2f \
 	expm1 \

dlls/msvcrt/math.c

@@ -5215,6 +5215,90 @@ short CDECL _fdtest(float *x)
     return _fdclass(*x);
 }
 
+static double erfc1(double x)
+{
+    static const double erx  = 8.45062911510467529297e-01,
+                 pa0  = -2.36211856075265944077e-03,
+                 pa1  =  4.14856118683748331666e-01,
+                 pa2  = -3.72207876035701323847e-01,
+                 pa3  =  3.18346619901161753674e-01,
+                 pa4  = -1.10894694282396677476e-01,
+                 pa5  =  3.54783043256182359371e-02,
+                 pa6  = -2.16637559486879084300e-03,
+                 qa1  =  1.06420880400844228286e-01,
+                 qa2  =  5.40397917702171048937e-01,
+                 qa3  =  7.18286544141962662868e-02,
+                 qa4  =  1.26171219808761642112e-01,
+                 qa5  =  1.36370839120290507362e-02,
+                 qa6  =  1.19844998467991074170e-02;
+
+    double s, P, Q;
+
+    s = fabs(x) - 1;
+    P = pa0 + s * (pa1 + s * (pa2 + s * (pa3 + s * (pa4 + s * (pa5 + s * pa6)))));
+    Q = 1 + s * (qa1 + s * (qa2 + s * (qa3 + s * (qa4 + s * (qa5 + s * qa6)))));
+    return 1 - erx - P / Q;
+}
+
+static double erfc2(uint32_t ix, double x)
+{
+    static const double ra0  = -9.86494403484714822705e-03,
+                 ra1  = -6.93858572707181764372e-01,
+                 ra2  = -1.05586262253232909814e+01,
+                 ra3  = -6.23753324503260060396e+01,
+                 ra4  = -1.62396669462573470355e+02,
+                 ra5  = -1.84605092906711035994e+02,
+                 ra6  = -8.12874355063065934246e+01,
+                 ra7  = -9.81432934416914548592e+00,
+                 sa1  =  1.96512716674392571292e+01,
+                 sa2  =  1.37657754143519042600e+02,
+                 sa3  =  4.34565877475229228821e+02,
+                 sa4  =  6.45387271733267880336e+02,
+                 sa5  =  4.29008140027567833386e+02,
+                 sa6  =  1.08635005541779435134e+02,
+                 sa7  =  6.57024977031928170135e+00,
+                 sa8  = -6.04244152148580987438e-02,
+                 rb0  = -9.86494292470009928597e-03,
+                 rb1  = -7.99283237680523006574e-01,
+                 rb2  = -1.77579549177547519889e+01,
+                 rb3  = -1.60636384855821916062e+02,
+                 rb4  = -6.37566443368389627722e+02,
+                 rb5  = -1.02509513161107724954e+03,
+                 rb6  = -4.83519191608651397019e+02,
+                 sb1  =  3.03380607434824582924e+01,
+                 sb2  =  3.25792512996573918826e+02,
+                 sb3  =  1.53672958608443695994e+03,
+                 sb4  =  3.19985821950859553908e+03,
+                 sb5  =  2.55305040643316442583e+03,
+                 sb6  =  4.74528541206955367215e+02,
+                 sb7  = -2.24409524465858183362e+01;
+
+    double s, R, S, z;
+    UINT64 iz;
+
+    if (ix < 0x3ff40000) /* |x| < 1.25 */
+        return erfc1(x);
+
+    x = fabs(x);
+    s = 1 / (x * x);
+    if (ix < 0x4006db6d) { /* |x| < 1/.35 ~ 2.85714 */
+        R = ra0 + s * (ra1 + s * (ra2 + s * (ra3 + s * (ra4 + s *
+                            (ra5 + s * (ra6 + s * ra7))))));
+        S = 1.0 + s * (sa1 + s * (sa2 + s * (sa3 + s * (sa4 + s *
+                            (sa5 + s * (sa6 + s * (sa7 + s * sa8)))))));
+    } else { /* |x| > 1/.35 */
+        R = rb0 + s * (rb1 + s * (rb2 + s * (rb3 + s * (rb4 + s *
+                            (rb5 + s * rb6)))));
+        S = 1.0 + s * (sb1 + s * (sb2 + s * (sb3 + s * (sb4 + s *
+                            (sb5 + s * (sb6 + s * sb7))))));
+    }
+    z = x;
+    iz = *(ULONGLONG*)&z;
+    iz &= 0xffffffff00000000ULL;
+    z = *(double*)&iz;
+    return exp(-z * z - 0.5625) * exp((z - x) * (z + x) + R / S) / x;
+}
+
 /*********************************************************************
  *      erf (MSVCR120.@)
  */
@@ -5354,10 +5438,52 @@ float CDECL erff(float x)
 
 /*********************************************************************
  *      erfc (MSVCR120.@)
+ *
+ * Copied from musl: src/math/erf.c
  */
 double CDECL erfc(double x)
 {
-    return unix_funcs->erfc( x );
+    static const double pp0  =  1.28379167095512558561e-01,
+                 pp1  = -3.25042107247001499370e-01,
+                 pp2  = -2.84817495755985104766e-02,
+                 pp3  = -5.77027029648944159157e-03,
+                 pp4  = -2.37630166566501626084e-05,
+                 qq1  =  3.97917223959155352819e-01,
+                 qq2  =  6.50222499887672944485e-02,
+                 qq3  =  5.08130628187576562776e-03,
+                 qq4  =  1.32494738004321644526e-04,
+                 qq5  = -3.96022827877536812320e-06;
+
+    double r, s, z, y;
+    UINT32 ix;
+    int sign;
+
+    ix = *(ULONGLONG*)&x >> 32;
+    sign = ix >> 31;
+    ix &= 0x7fffffff;
+    if (ix >= 0x7ff00000) {
+        /* erfc(nan)=nan, erfc(+-inf)=0,2 */
+        return 2 * sign + 1 / x;
+    }
+    if (ix < 0x3feb0000) { /* |x| < 0.84375 */
+        if (ix < 0x3c700000) /* |x| < 2**-56 */
+            return 1.0 - x;
+        z = x * x;
+        r = pp0 + z * (pp1 + z * (pp2 + z * (pp3 + z * pp4)));
+        s = 1.0 + z * (qq1 + z * (qq2 + z * (qq3 + z * (qq4 + z * qq5))));
+        y = r / s;
+        if (sign || ix < 0x3fd00000) { /* x < 1/4 */
+            return 1.0 - (x + x * y);
+        }
+        return 0.5 - (x - 0.5 + x * y);
+    }
+    if (ix < 0x403c0000) { /* 0.84375 <= |x| < 28 */
+        return sign ? 2 - erfc2(ix, x) : erfc2(ix, x);
+    }
+    if (sign)
+        return 2 - DBL_MIN;
+    *_errno() = ERANGE;
+    return fp_barrier(DBL_MIN) * DBL_MIN;
 }
 
 /*********************************************************************

dlls/msvcrt/unixlib.c

@@ -174,18 +174,6 @@ static double CDECL unix_erf(double x)
 }
 
 /*********************************************************************
- *      erfc
- */
-static double CDECL unix_erfc(double x)
-{
-#ifdef HAVE_ERFC
-    return erfc(x);
-#else
-    return 1 - unix_erf(x);
-#endif
-}
-
-/*********************************************************************
  *      exp
  */
 static double CDECL unix_exp( double x )
@@ -554,7 +542,6 @@ static const struct unix_funcs funcs =
     unix_cosh,
     unix_coshf,
     unix_erf,
-    unix_erfc,
     unix_exp,
     unix_expf,
     unix_exp2,

dlls/msvcrt/unixlib.h

@@ -34,7 +34,6 @@ struct unix_funcs
     double          (CDECL *cosh)(double x);
     float           (CDECL *coshf)(float x);
     double          (CDECL *erf)(double x);
-    double          (CDECL *erfc)(double x);
     double          (CDECL *exp)(double x);
     float           (CDECL *expf)(float x);
     double          (CDECL *exp2)(double x);

include/config.h.in

@@ -113,9 +113,6 @@
 /* Define to 1 if you have the `erf' function. */
 #undef HAVE_ERF
 
-/* Define to 1 if you have the `erfc' function. */
-#undef HAVE_ERFC
-
 /* Define to 1 if you have the `exp2' function. */
 #undef HAVE_EXP2