[gcc/devel/omp/gcc-10] Fortran : ICE for division by zero in declaration PR95882

[gcc/devel/omp/gcc-10] Fortran : ICE for division by zero in declaration PR95882

[Tobias Burnus]

https://gcc.gnu.org/g:8323d09e82345a1ca39f6630cdd22ccf4ef38a84

commit 8323d09e82345a1ca39f6630cdd22ccf4ef38a84
Author: Mark Eggleston <markeggleston@gcc.gnu.org>
Date:   Fri Aug 21 06:39:30 2020 +0100

    Fortran  : ICE for division by zero in declaration PR95882
    
    A length expression containing a divide by zero in a character
    declaration will result in an ICE if the constant is anymore
    complicated that a contant divided by a constant.
    
    The cause was that char_len_param_value can return MATCH_YES
    even if a divide by zero was seen.  Prior to returning check
    whether a divide by zero was seen and if so set it to MATCH_ERROR.
    
    2020-08-27  Mark Eggleston  <markeggleston@gcc.gnu.org>
    
    gcc/fortran
    
            PR fortran/95882
            * decl.c (char_len_param_value): Check gfc_seen_div0 and
            if it is set return MATCH_ERROR.
    
    2020-08-27  Mark Eggleston  <markeggleston@gcc.gnu.org>
    
    gcc/testsuite/
    
            PR fortran/95882
            * gfortran.dg/pr95882_1.f90: New test.
            * gfortran.dg/pr95882_2.f90: New test.
            * gfortran.dg/pr95882_3.f90: New test.
            * gfortran.dg/pr95882_4.f90: New test.
            * gfortran.dg/pr95882_5.f90: New test.
    
    (cherry picked from commit c336eda750d4e7a0827fedf995da955d6d88d5ca)

Diff:
---
 gcc/fortran/decl.c                      | 3 +++
 gcc/testsuite/gfortran.dg/pr95882_1.f90 | 8 ++++++++
 gcc/testsuite/gfortran.dg/pr95882_2.f90 | 6 ++++++
 gcc/testsuite/gfortran.dg/pr95882_3.f90 | 6 ++++++
 gcc/testsuite/gfortran.dg/pr95882_4.f90 | 7 +++++++
 gcc/testsuite/gfortran.dg/pr95882_5.f90 | 6 ++++++
 6 files changed, 36 insertions(+)

diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index 36326f77569..e6c500bf8d2 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -1146,6 +1146,9 @@ char_len_param_value (gfc_expr **expr, bool *deferred)
       gfc_free_expr (e);
     }
 
+  if (gfc_seen_div0)
+    m = MATCH_ERROR;
+
   return m;
 
 syntax:
diff --git a/gcc/testsuite/gfortran.dg/pr95882_1.f90 b/gcc/testsuite/gfortran.dg/pr95882_1.f90
new file mode 100644
index 00000000000..c254bddf494
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr95882_1.f90
@@ -0,0 +1,8 @@
+! { dg-do compile }
+
+module m
+   type t
+      character(((0)/0)) :: c  ! { dg-error "Division by zero" }
+   end type
+end
+
diff --git a/gcc/testsuite/gfortran.dg/pr95882_2.f90 b/gcc/testsuite/gfortran.dg/pr95882_2.f90
new file mode 100644
index 00000000000..d308f0c3181
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr95882_2.f90
@@ -0,0 +1,6 @@
+! { dg-do compile }
+
+module m
+   character(0/(0)) :: c = '123456789'  ! { dg-error "Division by zero" }
+end
+
diff --git a/gcc/testsuite/gfortran.dg/pr95882_3.f90 b/gcc/testsuite/gfortran.dg/pr95882_3.f90
new file mode 100644
index 00000000000..bd849135480
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr95882_3.f90
@@ -0,0 +1,6 @@
+! { dg-do compile }
+
+subroutine s(c)
+   character(((0)/0)) :: c  ! { dg-error "Division by zero" }
+end
+
diff --git a/gcc/testsuite/gfortran.dg/pr95882_4.f90 b/gcc/testsuite/gfortran.dg/pr95882_4.f90
new file mode 100644
index 00000000000..52892d32b8b
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr95882_4.f90
@@ -0,0 +1,7 @@
+! { dg-do compile }
+
+program p
+   character(((0)/0)) :: c  ! { dg-error "Division by zero" }
+   common /x/ c
+end
+
diff --git a/gcc/testsuite/gfortran.dg/pr95882_5.f90 b/gcc/testsuite/gfortran.dg/pr95882_5.f90
new file mode 100644
index 00000000000..dcdf5304052
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr95882_5.f90
@@ -0,0 +1,6 @@
+! { dg-do compile }
+
+program p
+   character(0/(0)) :: c = '123456789'  ! { dg-error "Division by zero" }
+   common c
+end