[PATCH] Fortran: set shape of initializers of zero-sized arrays [PR95374,PR104352]

[Harald Anlauf <anlauf@gmx.de>]

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Dear all,

the attached patch is neat, because it fixes a bug by removing code ;-)

When generating the initializer for a parameter array, we excepted
the case of size 0, which however prevented the detection of array
bounds violations and lead to ICEs in various places.  The solution
which removes the comparison for size > 0 also has the bonus that
it fixes a minor memory leak for the size==0 case...

Regtested on x86_64-pc-linux-gnu.  OK for mainline?

Thanks,
Harald


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From 9d2995d2c1cf5708e3297fc7cffb5184d45a65cb Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Wed, 17 May 2023 20:39:18 +0200
Subject: [PATCH] Fortran: set shape of initializers of zero-sized arrays
 [PR95374,PR104352]

gcc/fortran/ChangeLog:

	PR fortran/95374
	PR fortran/104352
	* decl.cc (add_init_expr_to_sym): Set shape of initializer also for
	zero-sized arrays, so that bounds violations can be detected later.

gcc/testsuite/ChangeLog:

	PR fortran/95374
	PR fortran/104352
	* gfortran.dg/zero_sized_13.f90: New test.
---
 gcc/fortran/decl.cc                         |  3 +--
 gcc/testsuite/gfortran.dg/zero_sized_13.f90 | 28 +++++++++++++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/zero_sized_13.f90

diff --git a/gcc/fortran/decl.cc b/gcc/fortran/decl.cc
index 9c4b40d4ac4..4c578d01ad4 100644
--- a/gcc/fortran/decl.cc
+++ b/gcc/fortran/decl.cc
@@ -2239,8 +2239,7 @@ add_init_expr_to_sym (const char *name, gfc_expr **initp, locus *var_locus)
 	      && gfc_is_constant_expr (init)
 	      && (init->expr_type == EXPR_CONSTANT
 		  || init->expr_type == EXPR_STRUCTURE)
-	      && spec_size (sym->as, &size)
-	      && mpz_cmp_si (size, 0) > 0)
+	      && spec_size (sym->as, &size))
 	    {
 	      array = gfc_get_array_expr (init->ts.type, init->ts.kind,
 					  &init->where);
diff --git a/gcc/testsuite/gfortran.dg/zero_sized_13.f90 b/gcc/testsuite/gfortran.dg/zero_sized_13.f90
new file mode 100644
index 00000000000..4035d458b32
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/zero_sized_13.f90
@@ -0,0 +1,28 @@
+! { dg-do compile }
+! { dg-options "-w" }
+!
+! PR fortran/95374
+! PR fortran/104352 - Various ICEs for bounds violation with zero-sized arrays
+!
+! Contributed by G. Steinmetz
+
+program p
+  implicit none
+  integer :: i
+  integer, parameter :: a(0)    = 0
+  integer, parameter :: b(0:-5) = 0
+  integer, parameter :: c(*) = [(a(i:i), i=0,0)] ! { dg-error "out of bounds" }
+  integer, parameter :: d(*) = [(b(i:i), i=1,1)] ! { dg-error "out of bounds" }
+  integer, parameter :: e(1) = [(a(i)  , i=1,1)] ! { dg-error "out of bounds" }
+  integer, parameter :: f(1) = [(a(i:i), i=1,1)] ! { dg-error "out of bounds" }
+  integer            :: g(1) = [(a(i:i), i=0,0)] ! { dg-error "out of bounds" }
+  integer            :: h(1) = [(a(i:i), i=1,1)] ! { dg-error "out of bounds" }
+  print *, [(a(i:i), i=0,0)] ! { dg-error "out of bounds" }
+  print *, [(a(i:i), i=1,1)] ! { dg-error "out of bounds" }
+  print *, any (a(1:1) == 1) ! { dg-error "out of bounds" }
+  print *, all (a(0:0) == 1) ! { dg-error "out of bounds" }
+  print *, sum (a(1:1))      ! { dg-error "out of bounds" }
+  print *, iall (a(0:0))     ! { dg-error "out of bounds" }
+  print *, minloc (a(0:0),1) ! { dg-error "out of bounds" }
+  print *, dot_product(a(1:1),a(1:1)) ! { dg-error "out of bounds" }
+end
--
2.35.3