[Bug fortran/109186] nearest(huge(x),-1.0_kind(x)) half of correct value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 anlauf at gcc dot gnu.org changed: What|Removed |Added Status|ASSIGNED|RESOLVED Target Milestone|--- |10.5 Resolution|--- |FIXED --- Comment #10 from anlauf at gcc dot gnu.org --- Fixed on all open branches. Closing. Thanks for the report!
[Bug fortran/109186] nearest(huge(x),-1.0_kind(x)) half of correct value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 --- Comment #9 from CVS Commits --- The releases/gcc-10 branch has been updated by Harald Anlauf : https://gcc.gnu.org/g:b9f6e7e234bab6ef8b5425c3e8b88bf8dfbc5089 commit r10-11265-gb9f6e7e234bab6ef8b5425c3e8b88bf8dfbc5089 Author: Harald Anlauf Date: Sun Mar 19 21:29:46 2023 +0100 Fortran: simplification of NEAREST for large argument [PR109186] gcc/fortran/ChangeLog: PR fortran/109186 * simplify.c (gfc_simplify_nearest): Fix off-by-one error in setting up real kind-specific maximum exponent for mpfr. gcc/testsuite/ChangeLog: PR fortran/109186 * gfortran.dg/nearest_6.f90: New test. (cherry picked from commit 4410a08b80cc40342eeaa5b6af824cd4352b218c)
[Bug fortran/109186] nearest(huge(x),-1.0_kind(x)) half of correct value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 --- Comment #8 from CVS Commits --- The releases/gcc-11 branch has been updated by Harald Anlauf : https://gcc.gnu.org/g:4b722050fe8e7f06a3e653f290a39ccdc4d03174 commit r11-10595-g4b722050fe8e7f06a3e653f290a39ccdc4d03174 Author: Harald Anlauf Date: Sun Mar 19 21:29:46 2023 +0100 Fortran: simplification of NEAREST for large argument [PR109186] gcc/fortran/ChangeLog: PR fortran/109186 * simplify.c (gfc_simplify_nearest): Fix off-by-one error in setting up real kind-specific maximum exponent for mpfr. gcc/testsuite/ChangeLog: PR fortran/109186 * gfortran.dg/nearest_6.f90: New test. (cherry picked from commit 4410a08b80cc40342eeaa5b6af824cd4352b218c)
[Bug fortran/109186] nearest(huge(x),-1.0_kind(x)) half of correct value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 --- Comment #7 from CVS Commits --- The releases/gcc-12 branch has been updated by Harald Anlauf : https://gcc.gnu.org/g:f1342c21b2acbdd1daa0f2519154f8ac911a800f commit r12-9310-gf1342c21b2acbdd1daa0f2519154f8ac911a800f Author: Harald Anlauf Date: Sun Mar 19 21:29:46 2023 +0100 Fortran: simplification of NEAREST for large argument [PR109186] gcc/fortran/ChangeLog: PR fortran/109186 * simplify.cc (gfc_simplify_nearest): Fix off-by-one error in setting up real kind-specific maximum exponent for mpfr. gcc/testsuite/ChangeLog: PR fortran/109186 * gfortran.dg/nearest_6.f90: New test. (cherry picked from commit 4410a08b80cc40342eeaa5b6af824cd4352b218c)
[Bug fortran/109186] nearest(huge(x),-1.0_kind(x)) half of correct value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 --- Comment #6 from CVS Commits --- The master branch has been updated by Harald Anlauf : https://gcc.gnu.org/g:4410a08b80cc40342eeaa5b6af824cd4352b218c commit r13-6762-g4410a08b80cc40342eeaa5b6af824cd4352b218c Author: Harald Anlauf Date: Sun Mar 19 21:29:46 2023 +0100 Fortran: simplification of NEAREST for large argument [PR109186] gcc/fortran/ChangeLog: PR fortran/109186 * simplify.cc (gfc_simplify_nearest): Fix off-by-one error in setting up real kind-specific maximum exponent for mpfr. gcc/testsuite/ChangeLog: PR fortran/109186 * gfortran.dg/nearest_6.f90: New test.
[Bug fortran/109186] nearest(huge(x),-1.0_kind(x)) half of correct value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 anlauf at gcc dot gnu.org changed: What|Removed |Added Assignee|unassigned at gcc dot gnu.org |anlauf at gcc dot gnu.org Status|NEW |ASSIGNED --- Comment #5 from anlauf at gcc dot gnu.org --- Submitted: https://gcc.gnu.org/pipermail/fortran/2023-March/059099.html
[Bug fortran/109186] nearest(huge(x),-1.0_kind(x)) half of correct value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 --- Comment #4 from anlauf at gcc dot gnu.org --- The following patch fixes this: diff --git a/gcc/fortran/simplify.cc b/gcc/fortran/simplify.cc index 20ea38e0007..35ae637a483 100644 --- a/gcc/fortran/simplify.cc +++ b/gcc/fortran/simplify.cc @@ -6114,7 +6112,7 @@ gfc_simplify_nearest (gfc_expr *x, gfc_expr *s) kind = gfc_validate_kind (BT_REAL, x->ts.kind, 0); mpfr_set_emin ((mpfr_exp_t) gfc_real_kinds[kind].min_exponent - mpfr_get_prec(result->value.real) + 1); - mpfr_set_emax ((mpfr_exp_t) gfc_real_kinds[kind].max_exponent - 1); + mpfr_set_emax ((mpfr_exp_t) gfc_real_kinds[kind].max_exponent); mpfr_check_range (result->value.real, 0, MPFR_RNDU); if (mpfr_sgn (s->value.real) > 0) The above code was apparently introduced with r0-84566-gb6f63e898498e6
[Bug fortran/109186] nearest(huge(x),-1.0_kind(x)) half of correct value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 anlauf at gcc dot gnu.org changed: What|Removed |Added CC||anlauf at gcc dot gnu.org Status|UNCONFIRMED |NEW Ever confirmed|0 |1 Last reconfirmed||2023-03-19 Keywords||wrong-code --- Comment #3 from anlauf at gcc dot gnu.org --- Confirmed. This is a compile-time issue. When the first argument of NEAREST is a variable and not a constant expression, I get the correct result: program p real, parameter :: x = huge(1.0) real :: y, z y = x z = nearest (y, -1.0) print *, nearest (x, -1.0), z end This prints: 1.70141173E+38 3.40282326E+38 Seems to affect all versions at least down to 7.
[Bug fortran/109186] nearest(huge(x),-1.0_kind(x)) half of correct value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 --- Comment #2 from john.harper at vuw dot ac.nz --- The results I expected were that nearest(huge(sp1),-sp1) would be near huge(sp1)/(1+epsilon(sp1)), nearest(huge(dp1),-dp1) would be near huge(dp1)/(1+epsilon(dp1)), nearest(huge(ep1),-ep1) would be near huge(ep1)/(1+epsilon(ep1)), nearest(huge(qp1),-qp1) would be near huge(qp1)/(1+epsilon(qp1)). The results from gfortran were different from those by a factor near 2. On compiling with ifort I got results close to what I had expected, which is why I thought the bug was not in my program. The g95 compiler (now about 10 years old) gave results identical to those of ifort except for ep = selected_real_kind(18) which ifort treats as if it were selected_real_kind(33) because ifort has only three real kinds. By the way I thought I was using gfortran 12.0. Compiling with -v said GNU Fortran (Ubuntu 12.1.0-2ubuntu1~22.04) version 12.1.0 (x86_64-linux-gnu) I wish to apologise for that error in my bug report. I got the same output on another machine with GNU Fortran (GCC) version 12.2.0 (x86_64-pc-linux-gnu) The factor 2 discrepancies become clearer in this version of my program, which has 4 more lines printing huge/nearest for the 4 real kinds. program nearesttest3 implicit none integer,parameter::sp = kind(1.0), dp=kind(1d0), ncases = 2, & ep = selected_real_kind(18),qp = selected_real_kind(33) character(*),parameter:: fmt(4) = & "(A,ES"//["16.08E2","26.17E3","30.20E4","44.34E4"]//")" character(24),dimension(2):: splist,dplist,eplist,qplist integer n real(sp),parameter::sp1 = 1.0_sp real(sp):: spx(ncases) = [huge(sp1),nearest(huge(sp1),-sp1)] data splist/'huge(sp1)','nearest(huge(sp1),-sp1)'/ real(dp),parameter::dp1 = 1.0_dp real(dp):: dpx(ncases) = [huge(dp1),nearest(huge(dp1),-dp1)] data dplist/'huge(dp1)','nearest(huge(dp1),-dp1)'/ real(ep),parameter::ep1 = 1.0_ep real(ep):: epx(ncases) = [huge(ep1),nearest(huge(ep1),-ep1)] data eplist/'huge(ep1)','nearest(huge(ep1),-ep1)'/ real(qp),parameter::qp1 = 1.0_qp real(qp):: qpx(ncases) = [huge(qp1),nearest(huge(qp1),-qp1)] data qplist/'huge(qp1)','nearest(huge(qp1),-qp1)'/ print fmt(1),(splist(n),spx(n),n=1,ncases) print fmt(1),'huge/nearest = ',huge(sp1)/nearest(huge(sp1),-sp1) print fmt(2),(dplist(n),dpx(n),n=1,ncases) print fmt(2),'huge/nearest = ',huge(dp1)/nearest(huge(dp1),-dp1) print fmt(3),(eplist(n),epx(n),n=1,ncases) print fmt(3),'huge/nearest = ',huge(ep1)/nearest(huge(ep1),-ep1) print fmt(4),(qplist(n),qpx(n),n=1,ncases) print fmt(4),'huge/nearest = ',huge(qp1)/nearest(huge(qp1),-qp1) end program nearesttest3 Its gfortran output: huge(sp1) 3.40282347E+38 nearest(huge(sp1),-sp1) 1.70141173E+38 huge/nearest = 2.E+00 huge(dp1) 1.79769313486231571E+308 nearest(huge(dp1),-dp1) 8.98846567431157854E+307 huge/nearest = 2.0E+000 huge(ep1) 1.18973149535723176502E+4932 nearest(huge(ep1),-ep1) 5.94865747678615882511E+4931 huge/nearest = 2.E+ huge(qp1) 1.1897314953572317650857593266280070E+4932 nearest(huge(qp1),-qp1) 5.9486574767861588254287966331400351E+4931 huge/nearest = 2.00E+ Its g95 output: uge(sp1) 3.40282347E+38 nearest(huge(sp1),-sp1) 3.40282326E+38 huge/nearest = 1.0012E+00 huge(dp1) 1.79769313486231571E+308 nearest(huge(dp1),-dp1) 1.79769313486231551E+308 huge/nearest = 1.00022E+000 huge(ep1) 1.18973149535723176502E+4932 nearest(huge(ep1),-ep1) 1.18973149535723176496E+4932 huge/nearest = 1.0011E+ huge(qp1) 1.1897314953572317650857593266280070E+4932 nearest(huge(qp1),-qp1) 1.1897314953572317650857593266280069E+4932 huge/nearest = 1.02E+ On Sun, 19 Mar 2023, jvdelisle at gcc dot gnu.org wrote: > Date: Sun, 19 Mar 2023 05:06:47 +0000 > From: jvdelisle at gcc dot gnu.org > To: John Harper > Subject: [Bug fortran/109186] nearest(huge(x), > -1.0_kind(x)) half of correct value > Resent-Date: Sun, 19 Mar 2023 18:06:59 +1300 (NZDT) > Resent-From: > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 > > Jerry DeLisle changed: > > What|Removed |Added > > CC||jvdelisle at gcc dot gnu.org > > --- Comment #1 from Jerry DeLisle --- > Can you clarify what you expect the correct results should be that you expect? > > -- > You are receiving this mail because: > You reported the bug. > -- John Harper, School of Mathematics and Statistics Victoria Univ. of Wellington, PO Box 600, Wellington 6140, New Zealand. e-mail john.har...@vuw.ac.nz phone +64(0) 4 463 5276
[Bug fortran/109186] nearest(huge(x),-1.0_kind(x)) half of correct value
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109186 Jerry DeLisle changed: What|Removed |Added CC||jvdelisle at gcc dot gnu.org --- Comment #1 from Jerry DeLisle --- Can you clarify what you expect the correct results should be that you expect?
