On 9/12/12, Mark Kettenis <mark.kette...@xs4all.nl> wrote: >> Date: Tue, 11 Sep 2012 17:03:39 -0700 >> From: Ian Lance Taylor <i...@google.com> >> >> On Tue, Sep 11, 2012 at 3:12 PM, Lawrence Crowl <cr...@googlers.com> >> wrote: >> > On 9/11/12, Andreas Schwab <sch...@linux-m68k.org> wrote: >> >> Mark Kettenis <mark.kette...@xs4all.nl> writes: >> >>> In file included from ../../../src/gcc/gcc/mcf.c:47:0: >> >>> ../../../src/gcc/gcc/mcf.c: In function 'void dump_fixup_edge(FILE*, >> >>> fixup_graph_type*, fixup_edge_p)': >> >>> ../../../src/gcc/gcc/system.h:288:78: error: integer overflow in >> >>> expression [-Werror=overflow] >> >> >> >> This is PR54528. >> > >> > The expression itself looks correct. I have not been able to >> > duplicate the problem on x86. I am now waiting on access to the >> > compile farm for access to a hppa system. Does anyone have more >> > specific information on the condition that generates the error? >> >> I haven't tried, but I bet you can get it to happen if you build a >> 32-bit compiler--that is, build a compiler using -m32 so that the >> compiler itself runs 32 bit code. > > I don't think that helps since I don't see the problem on OpenBSD/i386 > (i386-unknown-openbsd5.2) whith a strictly 32-bit compiler. As I > wrote earlier, I suspect the key factor is HOST_WIDE_INT being 32-bit, > which means 32-bit architectures that don't sey need_64bit_hwint in > config.gcc. The fact that m68k is affected as well strengthens my > suspicion. So I expect arm to show the problem as well. But people > probably haven't noticed since they cross-compile. > > Anyway the "diff" below seems to fix the issue. Guess the replacement > doesn't work! Should be a big enough clue for Lawrence to come up > with a proper fix. > > Index: fold-const.c > =================================================================== > --- fold-const.c (revision 191150) > +++ fold-const.c (working copy) > @@ -982,13 +982,15 @@ > break; > > case MINUS_EXPR: > -/* FIXME(crowl) Remove this code if the replacment works. > + /* FIXME(crowl) Remove this code if the replacment works. */ > +#if 1 > neg_double (op2.low, op2.high, &res.low, &res.high); > add_double (op1.low, op1.high, res.low, res.high, > &res.low, &res.high); > overflow = OVERFLOW_SUM_SIGN (res.high, op2.high, op1.high); > -*/ > +#else > res = op1.add_with_sign (-op2, false, &overflow); > +#endif > break; > > case MULT_EXPR:
My suspicions were on the shift operation. I will update the last patch I sent out with a fix. I will probably need help testing. -- Lawrence Crowl
