On Mon, Feb 21, 2005 at 09:14:22PM -0800, James E Wilson wrote: > Jonathan Wakely wrote: > >$ gcc4x -c bug.c -pedantic -save-temps > >bug.c: In function 'main': > >bug.c:1: error: floating constant exceeds range of 'long double' > > This is easy enough to explain. Grepping for the message shows that it > is printed from c-lex.c, and is only printed when -pedantic. > -save-temps means we run cc1 twice, once to produce the .i file, and > once to read the .i file. So the problem is either writing the .i file > or reading the .i file. > > Looking further, I noticed that FreeBSD sets the rounding mode to > 53-bits. real.c knows this, and computes values appropriately, i.e. > 96-bit values with 53-bits of fraction. Unfortunately, this value isn't > getting propagated properly to the C preprocessor when using > -save-temps/-E, and this problem exists because > init_adjust_machine_modes is run in the wrong place. It is run from > backend_init, but it needs to be run always, as we need it to compute > the FP predefined macros correctly. > > The value really is wrong, even though it is the same as gcc-3.4. It > has 11 too many bits of fraction. > > Targets using paired-double long double formats are probably also wrong. > Anything that overrides the normal IEEE FP formats will be wrong. > > Attached is a mostly untested patch to fix this. It works for your > testcase. And it now prints a different correct value of __LDBL_MAX__ > in the .i file.
Sorry for the late reply. It does indeed fix the problem I saw with 4.0 on FreeBSD, but I'm now seeing this with 3.4.4 20050228 too, so I think it's a regression introduced in the last 6 weeks or so. Is the same fix safe to apply to 3.4? I got no regressions testing on x86/FreeBSD a few days ago. I'm in the process of updating and re-testing current 3.4. jon > -- > Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com > 2005-02-21 James E Wilson <[EMAIL PROTECTED]> > > * toplev.c (backend_init): Don't call init_adjust_machine_modes here. > (do_compile): Do call it here. > > Index: toplev.c > =================================================================== > RCS file: /cvs/gcc/gcc/gcc/toplev.c,v > retrieving revision 1.942 > diff -p -p -r1.942 toplev.c > *** toplev.c 12 Feb 2005 00:26:52 -0000 1.942 > --- toplev.c 22 Feb 2005 04:58:04 -0000 > *************** process_options (void) > *** 1954,1961 **** > static void > backend_init (void) > { > - init_adjust_machine_modes (); > - > init_emit_once (debug_info_level == DINFO_LEVEL_NORMAL > || debug_info_level == DINFO_LEVEL_VERBOSE > #ifdef VMS_DEBUGGING_INFO > --- 1954,1959 ---- > *************** do_compile (void) > *** 2092,2097 **** > --- 2090,2100 ---- > /* Don't do any more if an error has already occurred. */ > if (!errorcount) > { > + /* This must be run always, because it is needed to compute the FP > + predefined macros, such as __LDBL_MAX__, for targets using non > + default FP formats. */ > + init_adjust_machine_modes (); > + > /* Set up the back-end if requested. */ > if (!no_backend) > backend_init ();
