Re: mathl warnings

[Paolo Bonzini]

> The mathl module, compiled on Cygwin with -Wall, yields several warnings:
>
> 1)
> acosl.c:186: warning: implicit declaration of function `asinl'
> acosl.c:186: warning: implicit declaration of function `sqrtl'
> asinl.c:186: warning: implicit declaration of function `sqrtl'
>
> Calling functions with 'long double' results when they are not declared
> most often yields wrong results, so this is probably not harmless.

This should be taken care of by the include of <math.h> at the top of 
the file.  I'd rather leave it to the gnulib hackers to understand it, 
because I didn't write that part.

Regarding the rest, I committed the attached patch to fix the problems. 
 Thanks.

> 2)
> trigl.c:217: warning: suggest explicit braces to avoid ambiguous `else'
>
> Look at trigl.c lines 215-216. The condition on x can never be true. What
> is the purpose of this code?

The wrong range is checked, I reorganized it to also avoid the warning 
(which was a red herring).

> 3)
> tanl.c:128: warning: 'flag' might be used uninitialized in this function
>
> The 'flag' is indeed used uninitialized.

Looking at the original glibc code, it must be initialized to 0.  I 
renamed it to invert.

Paolo

2008-04-15  Paolo Bonzini  <address@hidden>

        * lib/tanl.c (kernel_tanl): Rename flag to invert, initialize it
        to 0.
        * lib/trigl.c (ieee754_rem_pio2l): Fix range checks.

diff --git a/lib/tanl.c b/lib/tanl.c
index 64a84b8..11b63ad 100644
--- a/lib/tanl.c
+++ b/lib/tanl.c
@@ -125,7 +125,7 @@ long double
 kernel_tanl (long double x, long double y, int iy)
 {
   long double z, r, v, w, s, u, u1;
-  int flag, sign;
+  int invert = 0, sign;
 
   sign = 1;
   if (x < 0)
@@ -147,7 +147,7 @@ kernel_tanl (long double x, long double y, int iy)
     }
   if (x >= 0.6743316650390625) /* |x| >= 0.6743316650390625 */
     {
-      flag = 1;
+      invert = 1;
 
       z = pio4hi - x;
       w = pio4lo - y;
@@ -163,7 +163,7 @@ kernel_tanl (long double x, long double y, int iy)
   r = y + z * (s * r + y);
   r += TH * s;
   w = x + r;
-  if (flag)
+  if (invert)
     {
       v = (long double) iy;
       w = (v - 2.0 * (x - (w * w / (w + v) - r)));
diff --git a/lib/trigl.c b/lib/trigl.c
index ecdce32..6f9dcf5 100644
--- a/lib/trigl.c
+++ b/lib/trigl.c
@@ -205,7 +205,7 @@ ieee754_rem_pio2l (long double x, long double *y)
   int exp, n;
 
   if (x >= -0.78539816339744830961566084581987572104929234984377
-      && x < 0.78539816339744830961566084581987572104929234984377)
+      && x <= 0.78539816339744830961566084581987572104929234984377)
     /* x in <-pi/4, pi/4> */
     {
       y[0] = x;
@@ -213,9 +213,7 @@ ieee754_rem_pio2l (long double x, long double *y)
       return 0;
     }
 
-  if (x >= 2.35619449019234492884698253745962716314787704953131
-      && x < 2.35619449019234492884698253745962716314787704953131)
-    if (x > 0)
+  if (x > 0 && x < 2.35619449019234492884698253745962716314787704953131)
       {
        /* 113 + 93 bit PI is ok */
        z = x - PI_2_1;
@@ -223,7 +221,8 @@ ieee754_rem_pio2l (long double x, long double *y)
        y[1] = (z - y[0]) - PI_2_1t;
        return 1;
       }
-    else
+
+  if (x < 0 && x > -2.35619449019234492884698253745962716314787704953131)
       {
        /* 113 + 93 bit PI is ok */
        z = x + PI_2_1;