[gcc r13-5486] fortran: Set name for *LOC default BACK argument [PR108450]

[Mikael Morin <mikael@gcc.gnu.org>]

https://gcc.gnu.org/g:2e32a12c04c72f692a7bd119fd3e4e5b74392c9d

commit r13-5486-g2e32a12c04c72f692a7bd119fd3e4e5b74392c9d
Author: Mikael Morin <mikael@gcc.gnu.org>
Date:   Sun Jan 29 21:57:24 2023 +0100

    fortran: Set name for *LOC default BACK argument [PR108450]
    
    This change fixes an ICE caused by the double resolution of MINLOC,
    MAXLOC and FINDLOC expressions which get a default value for the BACK
    argument at resolution time.  That argument  is added without name,
    and argument reordering code is not prepared to handle unnamed arguments
    coming after named ones, so the second resolution causes a NULL pointer
    dereference.
    The problem is fixed by explicitly setting the argument name.
    
            PR fortran/108450
    
    gcc/fortran/ChangeLog:
    
            * check.cc (gfc_check_minloc_maxloc): Explicitly set argument name.
            (gfc_check_findloc): Ditto.
    
    gcc/testsuite/ChangeLog:
    
            * gfortran.dg/gomp/minmaxloc_1.f90: New test.

Diff:
---
 gcc/fortran/check.cc                           |  2 ++
 gcc/testsuite/gfortran.dg/gomp/minmaxloc_1.f90 | 32 ++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/gcc/fortran/check.cc b/gcc/fortran/check.cc
index ebcb8f39852..8c1ae8c2f00 100644
--- a/gcc/fortran/check.cc
+++ b/gcc/fortran/check.cc
@@ -3888,6 +3888,7 @@ gfc_check_minloc_maxloc (gfc_actual_arglist *ap)
     {
       b = gfc_get_logical_expr (gfc_logical_4_kind, NULL, 0);
       ap->next->next->next->next->expr = b;
+      ap->next->next->next->next->name = gfc_get_string ("back");
     }
 
   if (m == NULL && d != NULL && d->ts.type == BT_LOGICAL
@@ -3969,6 +3970,7 @@ gfc_check_findloc (gfc_actual_arglist *ap)
     {
       b = gfc_get_logical_expr (gfc_logical_4_kind, NULL, 0);
       ap->next->next->next->next->next->expr = b;
+      ap->next->next->next->next->next->name = gfc_get_string ("back");
     }
 
   if (m == NULL && d != NULL && d->ts.type == BT_LOGICAL
diff --git a/gcc/testsuite/gfortran.dg/gomp/minmaxloc_1.f90 b/gcc/testsuite/gfortran.dg/gomp/minmaxloc_1.f90
new file mode 100644
index 00000000000..b3691f774de
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/gomp/minmaxloc_1.f90
@@ -0,0 +1,32 @@
+! { dg-do compile }
+!
+! PR fortran/108450
+! This program used to cause an ICE because of the double resolution
+! of the maxloc expression and the addition of a hidden unnamed argument
+! during the first resolution.
+!
+! Original testcase from G. Steinmetz
+
+subroutine s1
+   integer :: a(8) = 0
+   integer :: l
+   integer :: n
+   !$omp atomic
+   n = maxloc(a, mask=l) ! { dg-error ".mask. argument of .maxloc. intrinsic at .1. must be LOGICAL" }
+end
+
+subroutine s2
+   integer :: a(8) = 0
+   integer :: l
+   integer :: n
+   !$omp atomic
+   n = minloc(a, mask=l) ! { dg-error ".mask. argument of .minloc. intrinsic at .1. must be LOGICAL" }
+end
+
+subroutine s3
+   integer :: a(8) = 0
+   integer :: l
+   integer :: n
+   !$omp atomic
+   n = findloc(a, 3, mask=l) ! { dg-error ".mask. argument of .findloc. intrinsic at .1. must be LOGICAL" }
+end