[Tinycc-devel] tcc doesn't set the inexact flag on inexact compile-time int-to-float conversion

[Vincent Lefevre]

tcc doesn't set the inexact flag on inexact compile-time int-to-float
conversion:

#include <stdio.h>
#include <fenv.h>

#pragma STDC FENV_ACCESS ON

void test1 (void)
{
  volatile float c;

  c = 0x7fffffbf;
  printf ("c = %a, inexact = %d\n", c, fetestexcept (FE_INEXACT));
}

void test2 (void)
{
  volatile float c;
  volatile int i = 0x7fffffbf;

  c = i;
  printf ("c = %a, inexact = %d\n", c, fetestexcept (FE_INEXACT));
}

int main (void)
{
  test1 ();
  test2 ();
  return 0;
}

With tin 0.9.25 under Linux/x86_64 (Debian):

$ tcc -Wall -O2 conv-int-flt-inex.c -o conv-int-flt-inex -lm
$ ./conv-int-flt-inex
c = 0x1.fffffep+30, inexact = 0
c = 0x1.fffffep+30, inexact = 32

FYI, GCC has the same problem:

  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57029

-- 
Vincent Lefèvre <address@hidden> - Web: <http://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)