Piotr Caban : msvcrt: Import erff implementation from musl.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 98525b04bc1de4c136d4fb0d70bdecaf0641f0e8
URL:    https://source.winehq.org/git/wine.git/?a=commit;h=98525b04bc1de4c136d4fb0d70bdecaf0641f0e8

Author: Piotr Caban <piotr at codeweavers.com>
Date:   Wed May 19 15:26:29 2021 +0200

msvcrt: Import erff implementation from musl.

Signed-off-by: Piotr Caban <piotr at codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard at winehq.org>

---

 configure             |  1 -
 configure.ac          |  1 -
 dlls/msvcrt/math.c    | 42 +++++++++++++++++++++++++++++++++++++++++-
 dlls/msvcrt/unixlib.c | 13 -------------
 dlls/msvcrt/unixlib.h |  1 -
 include/config.h.in   |  3 ---
 6 files changed, 41 insertions(+), 20 deletions(-)

diff --git a/configure b/configure
index 00c8378b4c6..9eb6cb7fd61 100755
--- a/configure
+++ b/configure
@@ -19624,7 +19624,6 @@ for ac_func in \
 	atanhf \
 	erf \
 	erfc \
-	erff \
 	exp2 \
 	exp2f \
 	expm1 \
diff --git a/configure.ac b/configure.ac
index e8b3d175fc9..d21882c7813 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2664,7 +2664,6 @@ AC_CHECK_FUNCS(\
 	atanhf \
 	erf \
 	erfc \
-	erff \
 	exp2 \
 	exp2f \
 	expm1 \
diff --git a/dlls/msvcrt/math.c b/dlls/msvcrt/math.c
index bd4df691e58..e0c28e25638 100644
--- a/dlls/msvcrt/math.c
+++ b/dlls/msvcrt/math.c
@@ -5306,10 +5306,50 @@ static float erfc2f(UINT32 ix, float x)
 
 /*********************************************************************
  *      erff (MSVCR120.@)
+ *
+ * Copied from musl: src/math/erff.c
  */
 float CDECL erff(float x)
 {
-    return unix_funcs->erff( x );
+    static const float efx8 =  1.0270333290e+00,
+                 pp0  =  1.2837916613e-01,
+                 pp1  = -3.2504209876e-01,
+                 pp2  = -2.8481749818e-02,
+                 pp3  = -5.7702702470e-03,
+                 pp4  = -2.3763017452e-05,
+                 qq1  =  3.9791721106e-01,
+                 qq2  =  6.5022252500e-02,
+                 qq3  =  5.0813062117e-03,
+                 qq4  =  1.3249473704e-04,
+                 qq5  = -3.9602282413e-06;
+
+    float r, s, z, y;
+    UINT32 ix;
+    int sign;
+
+    ix = *(UINT32*)&x;
+    sign = ix >> 31;
+    ix &= 0x7fffffff;
+    if (ix >= 0x7f800000) {
+        /* erf(nan)=nan, erf(+-inf)=+-1 */
+        return 1 - 2 * sign + 1 / x;
+    }
+    if (ix < 0x3f580000) { /* |x| < 0.84375 */
+        if (ix < 0x31800000) { /* |x| < 2**-28 */
+            /*avoid underflow */
+            return 0.125f * (8 * x + efx8 * x);
+        }
+        z = x * x;
+        r = pp0 + z * (pp1 + z * (pp2 + z * (pp3 + z * pp4)));
+        s = 1 + z * (qq1 + z * (qq2 + z * (qq3 + z * (qq4 + z * qq5))));
+        y = r / s;
+        return x + x * y;
+    }
+    if (ix < 0x40c00000) /* |x| < 6 */
+        y = 1 - erfc2f(ix, x);
+    else
+        y = 1 - FLT_MIN;
+    return sign ? -y : y;
 }
 
 /*********************************************************************
diff --git a/dlls/msvcrt/unixlib.c b/dlls/msvcrt/unixlib.c
index 77de4602918..9607ca94e7c 100644
--- a/dlls/msvcrt/unixlib.c
+++ b/dlls/msvcrt/unixlib.c
@@ -173,18 +173,6 @@ static double CDECL unix_erf(double x)
 #endif
 }
 
-/*********************************************************************
- *      erff
- */
-static float CDECL unix_erff(float x)
-{
-#ifdef HAVE_ERFF
-    return erff(x);
-#else
-    return unix_erf(x);
-#endif
-}
-
 /*********************************************************************
  *      erfc
  */
@@ -567,7 +555,6 @@ static const struct unix_funcs funcs =
     unix_coshf,
     unix_erf,
     unix_erfc,
-    unix_erff,
     unix_exp,
     unix_expf,
     unix_exp2,
diff --git a/dlls/msvcrt/unixlib.h b/dlls/msvcrt/unixlib.h
index 13912c68c99..58ec53d285c 100644
--- a/dlls/msvcrt/unixlib.h
+++ b/dlls/msvcrt/unixlib.h
@@ -35,7 +35,6 @@ struct unix_funcs
     float           (CDECL *coshf)(float x);
     double          (CDECL *erf)(double x);
     double          (CDECL *erfc)(double x);
-    float           (CDECL *erff)(float x);
     double          (CDECL *exp)(double x);
     float           (CDECL *expf)(float x);
     double          (CDECL *exp2)(double x);
diff --git a/include/config.h.in b/include/config.h.in
index d7738888e27..b0e1fb55332 100644
--- a/include/config.h.in
+++ b/include/config.h.in
@@ -116,9 +116,6 @@
 /* Define to 1 if you have the `erfc' function. */
 #undef HAVE_ERFC
 
-/* Define to 1 if you have the `erff' function. */
-#undef HAVE_ERFF
-
 /* Define to 1 if you have the `exp2' function. */
 #undef HAVE_EXP2