This is the mail archive of the gcc-bugs@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[Bug rtl-optimization/323] optimized code gives strange floating point results



------- Comment #127 from jsm28 at gcc dot gnu dot org  2009-03-30 01:57 -------
Fixed for C (and ObjC) for 4.5 with the new -fexcess-precision=standard
support.

The issue remains for other languages (and maybe for some m68k processors);
I quote from my original message
<http://gcc.gnu.org/ml/gcc-patches/2008-11/msg00105.html>:

  It would be possible to implement the option for non-C languages, to
  provide whatever predictable semantics are appropriate for those
  languages (whether or not described in their standards).  Note that
  bug 323 was originally reported with a C++ testcase.  If implemented
  for all languages, the option might supersede -ffloat-store.  Right
  now, -ffloat-store checks are scattered about the optimizers and it
  seems unlikely that -ffloat-store really implements any form of
  predictable semantics now; such semantic effect as it was intended to
  have could be better represented as an alias for a
  -fexcess-precision=standard option supported for all languages.  It
  would probably be most appropriate not to close bug 323 without having
  some form of predictable semantics available for each language.

and:

  I have not changed the m68k back end in this patch.  Thus the option
  may not be fully effective for the affected m68k processors (classic
  m68k with 68881, before 68040, only, not ColdFire, not 68040 or
  later).  If anyone wishes to make it fully effective for such
  processors they should copy the testcases to gcc.target/m68k/ and go
  through m68k insn patterns appropriately adjusting them.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=323


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]