regression in tgamma?

[Paul Zimmermann]

       Hi Jeff,

> I have modified er_lgamma.c, erf_lgamma.c, w_tgamma.c, wf_tgamma.c based on
> code changes in picolibc.
> I did not add the new ___ieee754_ sub-functions and instead modified the
> existing code assuming that the function
> was called with *signgam = 0.  We can always do a merge from picolibc in the
> future.
> 
> With the new code, the test runs as expected.
> 
> Paul, please confirm before tomorrow.

version b2f3d59 fails to compile on my x86_64 machine:

../../../../../newlib/libm/math/w_tgamma.c: In function ‘tgamma’:
../../../../../newlib/libm/math/w_tgamma.c:38:6: error: ‘errno’ undeclared (first use in this function)
   38 |      errno = EDOM;
      |      ^~~~~
../../../../../newlib/libm/math/w_tgamma.c:19:1: note: ‘errno’ is defined in header ‘<errno.h>’; did you forget to ‘#include <errno.h>’?
   18 | #include "fdlibm.h"
  +++ |+#include <errno.h>

../../../../../newlib/libm/math/w_tgamma.c:38:6: note: each undeclared identifier is reported only once for each function it appears in
   38 |      errno = EDOM;
      |      ^~~~~
../../../../../newlib/libm/math/w_tgamma.c:38:14: error: ‘EDOM’ undeclared (first use in this function)
   38 |      errno = EDOM;
      |              ^~~~
../../../../../newlib/libm/math/w_tgamma.c:40:14: error: ‘ERANGE’ undeclared (first use in this function)
   40 |      errno = ERANGE;
      |              ^~~~~~

It does after the following changes:

diff --git a/newlib/libm/math/w_tgamma.c b/newlib/libm/math/w_tgamma.c
index 0f90dd4c6..52d5d71d3 100644
--- a/newlib/libm/math/w_tgamma.c
+++ b/newlib/libm/math/w_tgamma.c
@@ -16,6 +16,7 @@
  */
 
 #include "fdlibm.h"
+#include <errno.h>
 
 #ifndef _DOUBLE_IS_32BITS
 
diff --git a/newlib/libm/math/wf_tgamma.c b/newlib/libm/math/wf_tgamma.c
index 80aacf757..504cb4c29 100644
--- a/newlib/libm/math/wf_tgamma.c
+++ b/newlib/libm/math/wf_tgamma.c
@@ -15,6 +15,7 @@
 
 #include "math.h"
 #include "fdlibm.h"
+#include <errno.h>
 
 #ifdef __STDC__
        float tgammaf(float x)
@@ -34,7 +35,6 @@
            errno = EDOM;
          else if (finite(x))
            errno = ERANGE;
-       }
        return y;
 #endif
 }

and my small test program gives:

zimmerma@tomate:/tmp/newlib-cygwin$ ./a.out 
x=-0x0p+0 y=-inf
x=-0x1.53f198fe3b278p+7 y=0x1.fd6d312572d9cp-1015

which is ok. I'll do some further tests.

Paul