[PATCH committed] Fix build failure with MPFR 2.4.x (gimple-ssa-sprintf.c)

[Richard Biener]

On Fri, 27 Jan 2017, Jakub Jelinek wrote:

> On Fri, Jan 27, 2017 at 08:41:59AM +0100, Rainer Orth wrote:
> > > On 01/24/2017 02:37 AM, Markus Trippelsdorf wrote:
> > >> MPFR_RNDx was introduced in MPFR 3.0.0. Since the minimal version that
> > >> gcc checks for is 2.4.0, this leads to a build failure.
> > >>
> > >> The fix is straightforward.
> > >>
> > >> Tested on x86_64-pc-linux-gnu. Committed to trunk as obvious.
> > >>
> > >> 	* gimple-ssa-sprintf.c (format_floating): Change MPFR_RNDx to
> > >> 	GMP_RNDx for compatibility.
> > >
> > > This was changed once before for this reason (in r240350).  I forgot
> > > all about it and put it back in my latest patch for some reason.  I
> > > don't remember why exactly but I suspect I might have been trying to
> > > overcome some MPFR oddity.  It might help to #undef the MPFR_RNDx
> > > macros after including <mpfr.h> to avoid this in the future.  In any
> > > event, thanks for the fix.
> > 
> > we certainly should do something like this: your latest patch introduced
> > the same failure again:
> > 
> > /vol/gcc/src/hg/trunk/local/gcc/gimple-ssa-sprintf.c: In function 'long long unsigned int {anonymous}::format_floating_max(tree, char, long long int)':
> > /vol/gcc/src/hg/trunk/local/gcc/gimple-ssa-sprintf.c:1501:27: error: 'MPFR_RNDN' was not declared in this scope
> >    mpfr_from_real (x, &rv, MPFR_RNDN);
> >                            ^
> > Makefile:1098: recipe for target 'gimple-ssa-sprintf.o' failed
> > make[3]: *** [gimple-ssa-sprintf.o] Error 1
> 
> So what about poisoning MPFR_RND{N,D,Z,U} then?

Works for me.

Richard.

> With mpfr 3.1.5 it seems to work, both when using system gcc (6.3.1)
> and when building in stage3.  I don't have mpfr 2.4.* around and apparently
> it is incompatible with gmp 6.1.x, so I'd have to build both gmp and mpfr
> (and likely mpc too).  Can you just quickly try this if it works for you?
> 
> Newer mpfr.h has:
> typedef enum {
>   MPFR_RNDN=0,  /* round to nearest, with ties to even */
>   MPFR_RNDZ,    /* round toward zero */
>   MPFR_RNDU,    /* round toward +Inf */
>   MPFR_RNDD,    /* round toward -Inf */
>   MPFR_RNDA,    /* round away from zero */
>   MPFR_RNDF,    /* faithful rounding (not implemented yet) */
>   MPFR_RNDNA=-1 /* round to nearest, with ties away from zero (mpfr_round) */
> } mpfr_rnd_t;
> 
> /* kept for compatibility with MPFR 2.4.x and before */
> #define GMP_RNDN MPFR_RNDN
> #define GMP_RNDZ MPFR_RNDZ
> #define GMP_RNDU MPFR_RNDU
> #define GMP_RNDD MPFR_RNDD
> 
> so the question is if it will work with compilers that pretend to be GCC
> (clang++, icc).  I've just tried it with both, clang++ 3.8.0 compiles it
> fine (with noisy warnings about various non-issues), icpc 16.0.2 does error
> out on a couple of unrelated things, but doesn't mention the *RND* stuff.
> icpc claims to be GCC 6.3.1 (maybe it always pretends to be the same version
> as system gcc?) and errors e.g. on:
> ../../gcc/hash-table.h(956): error: declaration is incompatible with function template "void hash_table<Descriptor, Allocator>::traverse_noresize<Argument,Callback>(Argument)" (declared at line 444)
>   hash_table<Descriptor, Allocator>::traverse_noresize (Argument argument)
> ../../gcc/gimple.h(62): error: identifier "__builtin_FILE" is undefined
> ../../gcc/gimple.h(63): error: identifier "__builtin_LINE" is undefined
> ../../gcc/gimple.h(64): error: identifier "__builtin_FUNCTION" is undefined
> 
> 2017-01-27  Jakub Jelinek  <jakub@redhat.com>
> 
> 	* realmpfr.h: Poison MPFR_RND{N,Z,U,D}.
> 	* gimple-ssa-sprintf.c (format_floating_max): Use GMP_RNDN
> 	instead of MPFR_RNDN.
> 
> --- gcc/realmpfr.h.jj	2017-01-01 12:45:39.000000000 +0100
> +++ gcc/realmpfr.h	2017-01-27 09:04:56.082042138 +0100
> @@ -32,5 +32,10 @@ extern void real_from_mpfr (REAL_VALUE_T
>  			    const real_format *, mp_rnd_t);
>  extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *, mp_rnd_t);
>  
> -#endif /* ! GCC_REALGMP_H */
> +#if (GCC_VERSION >= 3000)
> +  /* For compatibility with mpfr 2.4 and earlier, we want to only use
> +     GMP_RND*.  */
> +  #pragma GCC poison MPFR_RNDN MPFR_RNDZ MPFR_RNDU MPFR_RNDD
> +#endif
>  
> +#endif /* ! GCC_REALGMP_H */
> --- gcc/gimple-ssa-sprintf.c.jj	2017-01-27 08:49:03.000000000 +0100
> +++ gcc/gimple-ssa-sprintf.c	2017-01-27 08:53:52.911721864 +0100
> @@ -1498,7 +1498,7 @@ format_floating_max (tree type, char spe
>       round-to-nearest mode.  */
>    mpfr_t x;
>    mpfr_init2 (x, rfmt->p);
> -  mpfr_from_real (x, &rv, MPFR_RNDN);
> +  mpfr_from_real (x, &rv, GMP_RNDN);
>  
>    /* Return a value one greater to account for the leading minus sign.  */
>    return 1 + get_mpfr_format_length (x, "", prec, spec, 'D');
> 
> 
> 	Jakub
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)