[Bug fortran/48977] New: -fpe-trap=denormal on x86 GLIBC systems

[Bug fortran/48977] New: -fpe-trap=denormal on x86 GLIBC systems

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48977

           Summary: -fpe-trap=denormal  on x86 GLIBC systems
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: burnus@gcc.gnu.org


Kind of follow up to PR 38810 - and motivated by
http://groups.google.com/group/comp.lang.fortran/browse_thread/thread/894fb77cabc6e8c7

GLIBC (and POSIX) do not support FE_DENORMAL and thus -fpe-trap=denormal does
not work. However, gfortran has a target version for denormal trapping:

fpu-387.h has:
  if (options.fpe & GFC_FPE_DENORMAL) cw &= ~_FPU_MASK_DM;
[...]
  if (has_sse())
[...]
      if (options.fpe & GFC_FPE_DENORMAL) cw_sse &= ~(_FPU_MASK_DM << 7);

Expected: If FE_DENORMAL is not supported and target == fpu-387.h, the latter
is used.

(It could also be of interest for the IEEE modules.)

[Bug fortran/48977] -fpe-trap=denormal on x86 GLIBC systems

[ubizjak at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48977

--- Comment #1 from Uros Bizjak <ubizjak at gmail dot com> 2011-05-12 19:43:56 UTC ---
Why not just:

Index: configure.host
===================================================================
--- configure.host    (revision 173705)
+++ configure.host    (working copy)
@@ -20,12 +20,6 @@
 # DEFAULTS
 fpu_host='fpu-generic'

-# HOST-SPECIFIC OVERRIDES
-case "${host_cpu}" in
-  i?86 | x86_64)
-    fpu_host='fpu-387' ;;
-esac
-
 # CONFIGURATION-SPECIFIC OVERRIDES
 if test "x${have_feenableexcept}" = "xyes"; then
   fpu_host='fpu-glibc'
@@ -39,6 +33,12 @@
   fpu_host='fpu-aix'
 fi

+# HOST-SPECIFIC OVERRIDES
+case "${host_cpu}" in
+  i?86 | x86_64)
+    fpu_host='fpu-387' ;;
+esac
+
 # Some targets require additional compiler options for NaN/Inf.
 ieee_flags=
 case "${host_cpu}" in

[Bug fortran/48977] -fpe-trap=denormal on x86 GLIBC systems

[jb at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48977

Janne Blomqvist <jb at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
                URL|                            |http://gcc.gnu.org/ml/gcc-p
                   |                            |atches/2011-05/msg01447.htm
                   |                            |l
   Last reconfirmed|                            |2011.05.20 13:29:10
                 CC|                            |jb at gcc dot gnu.org
         AssignedTo|unassigned at gcc dot       |jb at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

--- Comment #2 from Janne Blomqvist <jb at gcc dot gnu.org> 2011-05-20 13:29:10 UTC ---
Patch: http://gcc.gnu.org/ml/gcc-patches/2011-05/msg01447.html

[Bug fortran/48977] -fpe-trap=denormal on x86 GLIBC systems

[jb at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48977

Janne Blomqvist <jb at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #4 from Janne Blomqvist <jb at gcc dot gnu.org> 2011-05-20 14:49:02 UTC ---
Fixed, closing.

[Bug fortran/48977] -fpe-trap=denormal on x86 GLIBC systems

[jb at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48977

--- Comment #3 from Janne Blomqvist <jb at gcc dot gnu.org> 2011-05-20 14:45:53 UTC ---
Author: jb
Date: Fri May 20 14:45:51 2011
New Revision: 173952

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=173952
Log:
PR 48977 Denormal exception on glibc targets

Modified:
    trunk/libgfortran/ChangeLog
    trunk/libgfortran/configure.host