Re: GNU Guile 2.1.6 released (beta) [numbers.c]

[Amirouche]

Le 20/01/2017 à 20:01, Matt Wette a écrit :

On Jan 19, 2017, at 7:01 PM, Matt Wette <address@hidden> wrote:

On Jan 18, 2017, at 6:26 PM, Andy Wingo <address@hidden> wrote:

We are pleased to announce GNU Guile release 2.1.6.

Guile 2.1.6 is the sixth pre-release in what will eventually become the
2.2 release series.  We encourage you to test this release and provide
feedback to address@hidden.

Saw this one last round.  Mac OS, now gcc-6.3.0:

;;; ("address@hidden" 1.0 -0.0)

FAIL: numbers.test: string->number: valid complex number strings

I am going to see if I can generate the assembly.

Short story: scm_c_make_polar is broken for the Mac.  Guile needs to decide if it want to use __sincos() on Mac, or suppress optimization, or ...

I was able to get the above to work (guile-2.1.5) by using

 SCM

+#ifdef __APPLE__

+__attribute__((optimize("O0")))

+#endif

 scm_c_make_polar (double mag, double ang)

In scm_c_make_polar, “gcc -O2”  turns sin(), cos() into cexp(), since cexp(i*x) = cos(x) + i*sin(x):

gcc -O0 =>

LM4339:

movq -32(%rbp), %rax

movd %rax, %xmm0

call _sin

movd %xmm0, %rax

movq %rax, -8(%rbp)

LM4340:

movq -32(%rbp), %rax

movd %rax, %xmm0

call _cos

movd %xmm0, %rax

movq %rax, -16(%rbp)

gcc -O2 =>

pxor %xmm0, %xmm0

LVL2703:

call _cexp

I wrote a little C program to show that cexp() does not preserve the zero-signed-ness:

 cos,sin: +1.000000 -0.000000

__sincos: +1.000000 -0.000000

    cexp: +1.000000 +0.000000

The scm_c_make_polar will use sincos() if available, but macOS does not have sincos(), it has __sincos().

#include <stdio.h>

#include <stdint.h>

#include <math.h>

#include <complex.h>

extern double z, p, n;

int main() {

  double complex c;

  double d, sine, cosine;

  d = z*n;

  printf(" cos,sin: %+f %+f\n", cos(d), sin(d));

  __sincos(d, &sine, &cosine);

  printf("__sincos: %+f %+f\n", cosine, sine);

  c = cexp(CMPLX(0.0, d));

  printf("    cexp: %+f %+f\n", creal(c), cimag(c));

}

double z = 0.0, p = +1.0, n = -1.0;

Incidentally, the above program will not compile on my machine w/ gcc-6.3.0.  “gcc -std=c11” or “gcc -std=c99” will not recognize the standard macro CMPLX().

wow!