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[01/17] math: Add e_gammaf_r to glibc code and style

Message ID 20241025182614.2022697-2-adhemerval.zanella@linaro.org
State New
Headers show
Series Add more CORE-MATH on libm | expand

Commit Message

Adhemerval Zanella Netto Oct. 25, 2024, 6:21 p.m. UTC
Also remove the use of builtins in favor of standard names, compiler
already inline them (if supported) with current compiler options.
It also fixes and issue where __builtin_roundeven is not support on
gcc older than version 10.

Checked on x86_64-linux-gnu and i686-linux_gnu.

Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
---
 sysdeps/ieee754/flt-32/e_gammaf_r.c | 178 ++++++++++++++++------------
 sysdeps/m68k/m680x0/fpu/math_errf.c |   1 -
 2 files changed, 101 insertions(+), 78 deletions(-)
 delete mode 100644 sysdeps/m68k/m680x0/fpu/math_errf.c
diff mbox series

Patch

diff --git a/sysdeps/ieee754/flt-32/e_gammaf_r.c b/sysdeps/ieee754/flt-32/e_gammaf_r.c
index 90ed3b4890..8c32d9bf5d 100644
--- a/sysdeps/ieee754/flt-32/e_gammaf_r.c
+++ b/sysdeps/ieee754/flt-32/e_gammaf_r.c
@@ -37,9 +37,7 @@  SOFTWARE.
 #include <stddef.h>
 #include <libm-alias-finite.h>
 #include <math-narrow-eval.h>
-
-typedef union {float f; uint32_t u;} b32u32_u;
-typedef union {double f; uint64_t u;} b64u64_u;
+#include "math_config.h"
 
 float
 __ieee754_gammaf_r (float x, int *signgamp)
@@ -54,97 +52,123 @@  __ieee754_gammaf_r (float x, int *signgamp)
 
   /* List of exceptional cases. Each entry contains the 32-bit encoding u of x,
      a binary32 approximation f of gamma(x), and a correction term df.  */
-  static const struct {uint32_t u; float f, df;} tb[] = {
-    {0x27de86a9u, 0x1.268266p+47f, 0x1p22f},      // x = 0x1.bd0d52p-48
-    {0x27e05475u, 0x1.242422p+47f, 0x1p22f},      // x = 0x1.c0a8eap-48
-    {0xb63befb3u, -0x1.5cb6e4p+18f, 0x1p-7f},     // x = -0x1.77df66p-19
-    {0x3c7bb570u, 0x1.021d9p+6f, 0x1p-19f},       // x = 0x1.f76aep-7
-    {0x41e886d1u, 0x1.33136ap+98f, 0x1p73f},      // x = 0x1.d10da2p+4
-    {0xc067d177u, 0x1.f6850cp-3f, 0x1p-28f},      // x = -0x1.cfa2eep+1
-    {0xbd99da31u, -0x1.befe66p+3, -0x1p-22f},     // x = -0x1.33b462p-4
-    {0xbf54c45au, -0x1.a6b4ecp+2, +0x1p-23f},     // x = -0x1.a988b4p-1
-    {0x41ee77feu, 0x1.d3631cp+101, -0x1p-76f},    // x = 0x1.dceffcp+4
-    {0x3f843a64u, 0x1.f6c638p-1, 0x1p-26f},       // x = 0x1.0874c8p+0
+  static const struct
+  {
+    uint32_t u;
+    float f, df;
+  } tb[] = {
+    { 0x27de86a9u, 0x1.268266p+47f, 0x1p22f },	 /* x = 0x1.bd0d52p-48 */
+    { 0x27e05475u, 0x1.242422p+47f, 0x1p22f },	 /* x = 0x1.c0a8eap-48 */
+    { 0xb63befb3u, -0x1.5cb6e4p+18f, 0x1p-7f },	 /* x = -0x1.77df66p-19 */
+    { 0x3c7bb570u, 0x1.021d9p+6f, 0x1p-19f },	 /* x = 0x1.f76aep-7 */
+    { 0x41e886d1u, 0x1.33136ap+98f, 0x1p73f },	 /* x = 0x1.d10da2p+4 */
+    { 0xc067d177u, 0x1.f6850cp-3f, 0x1p-28f },	 /* x = -0x1.cfa2eep+1 */
+    { 0xbd99da31u, -0x1.befe66p+3, -0x1p-22f },	 /* x = -0x1.33b462p-4 */
+    { 0xbf54c45au, -0x1.a6b4ecp+2, +0x1p-23f },	 /* x = -0x1.a988b4p-1 */
+    { 0x41ee77feu, 0x1.d3631cp+101, -0x1p-76f }, /* x = 0x1.dceffcp+4 */
+    { 0x3f843a64u, 0x1.f6c638p-1, 0x1p-26f },	 /* x = 0x1.0874c8p+0 */
   };
 
-  b32u32_u t = {.f = x};
-  uint32_t ax = t.u<<1;
-  if(__builtin_expect(ax>=(0xffu<<24), 0)){ /* x=NaN or +/-Inf */
-    if(ax==(0xffu<<24)){ /* x=+/-Inf */
-      if(t.u>>31){ /* x=-Inf */
-        return x / x; /* will raise the "Invalid operation" exception */
-      }
-      return x; /* x=+Inf */
+  uint32_t t = asuint (x);
+  uint32_t ax = t << 1;
+  if (__glibc_unlikely (ax >= (0xffu << 24)))
+    { /* x=NaN or +/-Inf */
+      if (ax == (0xffu << 24))
+	{ /* x=+/-Inf */
+	  if (t >> 31) /* x=-Inf */
+	    return __math_invalidf (x);
+	  return x; /* x=+Inf */
+	}
+      return x + x; /* x=NaN, where x+x ensures the "Invalid operation"
+		       exception is set if x is sNaN */
     }
-    return x + x; /* x=NaN, where x+x ensures the "Invalid operation"
-                     exception is set if x is sNaN */
-  }
   double z = x;
-  if(__builtin_expect(ax<0x6d000000u, 0)){ /* |x| < 0x1p-18 */
-    volatile double d = (0x1.fa658c23b1578p-1 - 0x1.d0a118f324b63p-1*z)*z - 0x1.2788cfc6fb619p-1;
-    double f = 1.0/z + d;
-    float r = f;
-    b64u64_u rt = {.f = f};
-    if(((rt.u+2)&0xfffffff) < 4){
-      for(unsigned i=0;i<sizeof(tb)/sizeof(tb[0]);i++)
-	if(t.u==tb[i].u) return tb[i].f + tb[i].df;
+  if (__glibc_unlikely (ax < 0x6d000000u))
+    { /* |x| < 0x1p-18 */
+      volatile double d = (0x1.fa658c23b1578p-1 - 0x1.d0a118f324b63p-1 * z)
+	* z - 0x1.2788cfc6fb619p-1;
+      double f = 1.0 / z + d;
+      float r = f;
+      uint64_t rt = asuint64 (f);
+      if (((rt + 2) & 0xfffffff) < 4)
+	{
+	  for (unsigned i = 0; i < sizeof (tb) / sizeof (tb[0]); i++)
+	    if (t == tb[i].u)
+	      return tb[i].f + tb[i].df;
+	}
+      return r;
+    }
+  float fx = floorf (x);
+  if (__glibc_unlikely (x >= 0x1.18522p+5f))
+    {
+      /* Overflow case. The original CORE-MATH code returns 0x1p127f *
+	 0x1p127f, but apparently some compilers replace this by +Inf.  */
+      return math_narrow_eval (x * 0x1p127f);
     }
-    return r;
-  }
-  float fx = __builtin_floorf(x);
-  if(__builtin_expect(x >= 0x1.18522p+5f, 0)){
-    /* Overflow case. The original CORE-MATH code returns 0x1p127f * 0x1p127f,
-       but apparently some compilers replace this by +Inf.  */
-    return math_narrow_eval (x * 0x1p127f);
-  }
   /* compute k only after the overflow check, otherwise the case to integer
      might overflow */
   int k = fx;
-  if(__builtin_expect(fx==x, 0)){ /* x is integer */
-    if(x == 0.0f){
-      return 1.0f/x;
+  if (__glibc_unlikely (fx == x))
+    { /* x is integer */
+      if (x == 0.0f)
+	return 1.0f / x;
+      if (x < 0.0f)
+	return __math_invalidf (0.0f);
+      double t0 = 1, x0 = 1;
+      for (int i = 1; i < k; i++, x0 += 1.0)
+	t0 *= x0;
+      return t0;
     }
-    if(x < 0.0f){
-      return 0.0f / 0.0f; /* should raise the "Invalid operation" exception */
+  if (__glibc_unlikely (x < -42.0f))
+    { /* negative non-integer */
+      /* For x < -42, x non-integer, |gamma(x)| < 2^-151.  */
+      static const float sgn[2] = { 0x1p-127f, -0x1p-127f };
+      /* Underflows always happens */
+      return math_narrow_eval (0x1p-127f * sgn[k & 1]);
     }
-    double t0 = 1, x0 = 1;
-    for(int i=1; i<k; i++, x0 += 1.0) t0 *= x0;
-    return t0;
-  }
-  if(__builtin_expect(x<-42.0f, 0)){ /* negative non-integer */
-    /* For x < -42, x non-integer, |gamma(x)| < 2^-151.  */
-    static const float sgn[2] = {0x1p-127f, -0x1p-127f};
-    /* Underflows always happens */
-    return math_narrow_eval (0x1p-127f * sgn[k&1]);
-  }
-  /* The array c[] stores a degree-15 polynomial approximation for gamma(x).  */
+  /* The array c[] stores a degree-15 polynomial approximation for gamma(x). */
   static const double c[] =
-    {0x1.c9a76be577123p+0, 0x1.8f2754ddcf90dp+0, 0x1.0d1191949419bp+0, 0x1.e1f42cf0ae4a1p-2,
-     0x1.82b358a3ab638p-3, 0x1.e1f2b30cd907bp-5, 0x1.240f6d4071bd8p-6, 0x1.1522c9f3cd012p-8,
-     0x1.1fd0051a0525bp-10, 0x1.9808a8b96c37ep-13, 0x1.b3f78e01152b5p-15, 0x1.49c85a7e1fd04p-18,
-     0x1.471ca49184475p-19, -0x1.368f0b7ed9e36p-23, 0x1.882222f9049efp-23, -0x1.a69ed2042842cp-25};
+    {
+      0x1.c9a76be577123p+0,  0x1.8f2754ddcf90dp+0,   0x1.0d1191949419bp+0,
+      0x1.e1f42cf0ae4a1p-2,  0x1.82b358a3ab638p-3,   0x1.e1f2b30cd907bp-5,
+      0x1.240f6d4071bd8p-6,  0x1.1522c9f3cd012p-8,   0x1.1fd0051a0525bp-10,
+      0x1.9808a8b96c37ep-13, 0x1.b3f78e01152b5p-15,  0x1.49c85a7e1fd04p-18,
+      0x1.471ca49184475p-19, -0x1.368f0b7ed9e36p-23, 0x1.882222f9049efp-23,
+      -0x1.a69ed2042842cp-25
+   };
 
-  double m = z - 0x1.7p+1, i = __builtin_roundeven(m), step = __builtin_copysign(1.0,i);
-  double d = m - i, d2 = d*d, d4 = d2*d2, d8 = d4*d4;
-  double f = (c[0] + d*c[1]) + d2*(c[2] + d*c[3]) + d4*((c[4] + d*c[5]) + d2*(c[6] + d*c[7]))
-    + d8*((c[8] + d*c[9]) + d2*(c[10] + d*c[11]) + d4*((c[12] + d*c[13]) + d2*(c[14] + d*c[15])));
-  int jm = __builtin_fabs(i);
+  double m = z - 0x1.7p+1;
+  double i = roundeven (m);
+  double step = copysign (1.0, i);
+  double d = m - i, d2 = d * d, d4 = d2 * d2, d8 = d4 * d4;
+  double f = (c[0] + d * c[1]) + d2 * (c[2] + d * c[3])
+	     + d4 * ((c[4] + d * c[5]) + d2 * (c[6] + d * c[7]))
+	     + d8 * ((c[8] + d * c[9]) + d2 * (c[10] + d * c[11])
+		     + d4 * ((c[12] + d * c[13]) + d2 * (c[14] + d * c[15])));
+  int jm = fabs (i);
   double w = 1;
-  if(jm){
-    z -= 0.5 + step*0.5;
-    w = z;
-    for(int j=jm-1; j; j--) {z -= step; w *= z;}
-  }
-  if(i<=-0.5) w = 1/w;
+  if (jm)
+    {
+      z -= 0.5 + step * 0.5;
+      w = z;
+      for (int j = jm - 1; j; j--)
+	{
+	  z -= step;
+	  w *= z;
+	}
+    }
+  if (i <= -0.5)
+    w = 1 / w;
   f *= w;
-  b64u64_u rt = {.f = f};
+  uint64_t rt = asuint64 (f);
   float r = f;
   /* Deal with exceptional cases.  */
-  if(__builtin_expect(((rt.u+2)&0xfffffff) < 8, 0)){
-    for(unsigned j=0;j<sizeof(tb)/sizeof(tb[0]);j++) {
-      if(t.u==tb[j].u) return tb[j].f + tb[j].df;
+  if (__glibc_unlikely (((rt + 2) & 0xfffffff) < 8))
+    {
+      for (unsigned j = 0; j < sizeof (tb) / sizeof (tb[0]); j++)
+	if (t == tb[j].u)
+	  return tb[j].f + tb[j].df;
     }
-  }
   return r;
 }
 libm_alias_finite (__ieee754_gammaf_r, __gammaf_r)
diff --git a/sysdeps/m68k/m680x0/fpu/math_errf.c b/sysdeps/m68k/m680x0/fpu/math_errf.c
deleted file mode 100644
index 1cc8931700..0000000000
--- a/sysdeps/m68k/m680x0/fpu/math_errf.c
+++ /dev/null
@@ -1 +0,0 @@ 
-/* Not needed.  */