The attached patch addresses ICEs on several situations with zero-length
arrays of strings or zero-length substrings, which were caused by a NULL
pointer dereference in those particular situations.
To the reviewer: I am not 100% sure that my solution is correct, but it
solves the issues reported and regtests cleanly on x86_64-pc-linux-gnu.
OK for trunk? Backports?
Thanks,
Harald
P.S.: the PR has another ICE with integer array constructors which is
unrelated and under investigation.
2019-03-05 Harald Anlauf <anl...@gmx.de>
PR fortran/71203
* expr.c (simplify_const_ref): Avoid null pointer dereference.
2019-03-05 Harald Anlauf <anl...@gmx.de>
PR fortran/71203
* gfortran.dg/substr_8.f90: New test.
Index: gcc/fortran/expr.c
===================================================================
--- gcc/fortran/expr.c (revision 269400)
+++ gcc/fortran/expr.c (working copy)
@@ -1897,8 +1897,14 @@
string_len = 0;
if (!p->ts.u.cl)
- p->ts.u.cl = gfc_new_charlen (p->symtree->n.sym->ns,
- NULL);
+ {
+ if (p->symtree)
+ p->ts.u.cl = gfc_new_charlen (p->symtree->n.sym->ns,
+ NULL);
+ else
+ p->ts.u.cl = gfc_new_charlen (gfc_current_ns,
+ NULL);
+ }
else
gfc_free_expr (p->ts.u.cl->length);
Index: gcc/testsuite/gfortran.dg/substr_8.f90
===================================================================
--- gcc/testsuite/gfortran.dg/substr_8.f90 (nonexistent)
+++ gcc/testsuite/gfortran.dg/substr_8.f90 (working copy)
@@ -0,0 +1,15 @@
+! { dg-do run }
+! PR fortran/71203 - used to ICE on zero-length arrays or substrings
+! Derived from original test cases by Gerhard Steinmetz
+
+program p
+ implicit none
+ character(3), parameter :: a(4) = ' '
+ character(*), parameter :: b(4) = 'abc'
+ character(*), parameter :: x(*) = a(2:2)(3:1)
+ character(*), parameter :: y(*) = a(2:1)(3:1)
+ character(*), parameter :: z(*) = b(2:1)(2:3)
+ if (size (x) /= 1 .or. len(x) /= 0) stop 1
+ if (size (y) /= 0 .or. len(y) /= 0) stop 2
+ if (size (z) /= 0 .or. len(z) /= 2) stop 3
+end
