Hi all, hi Harald,
attached patch fixes a runtime out-of-bounds error when an iterator of an
implied do-loop was not substituted as expected. The resulting code would still
use the uninitialized iterator variable which then lead to out-of-bounds
accesses.
Harald, I did not look at the patch you put into the PR and reported to have
got stuck on just to not suffer from the same fate. Unfortunately I did just
the same with the same insufficient result. It took me a lot of head scratching
to come up with the this solution. Please have an in-depth look into it.
Regtests fine on x86_64-pc-linux-gnu / F41. Ok for mainline?
Regards,
Andre
--
Andre Vehreschild * Email: vehre ad gmx dot de
From faabad5c90b7505b7e118ff3fa1dcbfb4ff4d428 Mon Sep 17 00:00:00 2001
From: Andre Vehreschild <ve...@gcc.gnu.org>
Date: Fri, 27 Jun 2025 11:42:54 +0200
Subject: [PATCH] Fortran: Allow for iterator substitution in array
constructors [PR119106]
PR fortran/119106
gcc/fortran/ChangeLog:
* expr.cc (simplify_constructor): Do not simplify constants.
(gfc_simplify_expr): Continue to simplify expression when an
iterator is present.
gcc/testsuite/ChangeLog:
* gfortran.dg/array_constructor_58.f90: New test.
---
gcc/fortran/expr.cc | 5 +++--
.../gfortran.dg/array_constructor_58.f90 | 17 +++++++++++++++++
2 files changed, 20 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gfortran.dg/array_constructor_58.f90
diff --git a/gcc/fortran/expr.cc b/gcc/fortran/expr.cc
index b0495b7733e..b8d04ff6f36 100644
--- a/gcc/fortran/expr.cc
+++ b/gcc/fortran/expr.cc
@@ -1372,7 +1372,7 @@ simplify_constructor (gfc_constructor_base base, int type)
|| !gfc_simplify_expr (c->iterator->step, type)))
return false;
- if (c->expr)
+ if (c->expr && c->expr->expr_type != EXPR_CONSTANT)
{
/* Try and simplify a copy. Replace the original if successful
but keep going through the constructor at all costs. Not
@@ -2469,7 +2469,8 @@ gfc_simplify_expr (gfc_expr *p, int type)
{
if (!simplify_parameter_variable (p, type))
return false;
- break;
+ if (!iter_stack)
+ break;
}
if (type == 1)
diff --git a/gcc/testsuite/gfortran.dg/array_constructor_58.f90 b/gcc/testsuite/gfortran.dg/array_constructor_58.f90
new file mode 100644
index 00000000000..1473be0da01
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/array_constructor_58.f90
@@ -0,0 +1,17 @@
+!{ dg-do run }
+
+! Contributed by Federico Perini <federico.per...@gmail.com>
+! Check that PR fortran/119106 is fixed.
+
+program char_param_array
+implicit none
+character, parameter :: p(5) = ['1','2','3','4','5']
+character, save :: n(5) = ['1','2','3','4','5']
+integer :: i(10), j
+
+i = 4
+if (any([(n(i(j)),j=1,10)] /= '4')) stop 1 ! OK
+if (any([(p(i(j)),j=1,10)] /= '4')) stop 2 ! used to runtime out-of-bounds error
+
+end program char_param_array
+
--
2.50.1
