Re: [Tinycc-devel] Fwd: Bug#322913: tcc: _Bool exists but doesn't comply with C99

[Marcelo Jimenez]

Please try the following patch:

Index: tcc.c
===================================================================
RCS file: /cvsroot/tinycc/tinycc/tcc.c,v
retrieving revision 1.172
diff -u -r1.172 tcc.c
--- tcc.c       17 Jun 2005 22:05:58 -0000      1.172
+++ tcc.c       30 Aug 2005 05:23:36 -0000
@@ -5822,6 +5822,7 @@
             /* we handle char/short/etc... with generic code */
             if (dbt != (VT_INT | VT_UNSIGNED) &&
                 dbt != (VT_LLONG | VT_UNSIGNED) &&
+                dbt != VT_BOOL &&
                 dbt != VT_LLONG)
                 dbt = VT_INT;
             if (c) {
@@ -5836,6 +5837,10 @@
                     case VT_DOUBLE: vtop->c.ui = (unsigned
int)vtop->c.d; break;
                     case VT_LDOUBLE: vtop->c.ui = (unsigned
int)vtop->c.d; break;
                     }
+                    break;
+               case VT_BOOL:
+                    vpushi(0);
+                    gen_op(TOK_NE);
                     break;
                 default:
                     /* int case */

===================================================================

Hi,

A Debian user reported this bug about C99 compliance in TCC.

-------------------- Start of forwarded message --------------------
From: Hrvoje Niksic <address@hidden>
Subject: Bug#322913: tcc: _Bool exists but doesn't comply with C99
To: Debian Bug Tracking System <address@hidden>
Date: Sat, 13 Aug 2005 16:02:18 +0200

Package: tcc
Version: 0.9.23-1
Severity: normal

Tcc doesn't correctly implement casts from floating point types to _Bool. 
According to C99, such casts must return true for all numbers except 0:

   When any scalar value is converted to _Bool, the result is 0 if the value
   compares equal to 0; otherwise, the result is 1.

This means that (_Bool) 0.1 must be 1; with tcc it's 0.  The following
trivial program can be used to test this:

#include <stdio.h>
int
main (void)
{
  printf ("%d\n", (_Bool) 0.1);
  return 0;
}

The program prints 1 under Gcc (and other C99-compliant compilers I tested
it with, such as Sun's cc) and 0 under Tcc.  I know that Tcc doesn't aim for
C99 conformance, but it's confusing that it implements the _Bool type which
comes from C99, but not the associated semantics.

-------------------- End of forwarded message --------------------

Thanks,

-- 
  ,''`.
 : :' :        Romain Francoise <address@hidden>
 `. `'         http://people.debian.org/~rfrancoise/
   `-

float-to-bool-cast.patch
Description: Text Data