Dear Fortranners,
specifying invalid constant array declarations (e.g. real array bounds)
could lead to an ICE because the array specs were checked for consistency.
A possible solution is to try an early simplification before doing that
check and was suggested by Steve.
However, regtesting did reveal that bad declarations involving e.g.
arithmetic errors - like division by zero - were now handled differently.
(The relevant testcase was gfortran.dg/arith_divide_2.f90).
I therefore added a new function gfc_try_simplify_expr that accepts the
simplification only if no error occurs. This allows discovery of
arithmetic errors also at later stages and will be used here.
Regtested on x86_64-pc-linux-gnu. OK for mainline?
Thanks,
Harald
From 27f981bd1e9611373e4565c1d350b1da3eb653f0 Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anl...@gmx.de>
Date: Thu, 2 Dec 2021 22:33:49 +0100
Subject: [PATCH] Fortran: improve checking of array specifications
gcc/fortran/ChangeLog:
PR fortran/103505
* array.c (match_array_element_spec): Try to simplify array
element specifications to improve early checking.
* expr.c (gfc_try_simplify_expr): New. Try simplification of an
expression via gfc_simplify_expr. When an error occurs, roll
back.
* gfortran.h (gfc_try_simplify_expr): Declare it.
gcc/testsuite/ChangeLog:
PR fortran/103505
* gfortran.dg/pr103505.f90: New test.
Co-authored-by: Steven G. Kargl <ka...@gcc.gnu.org>
---
gcc/fortran/array.c | 4 ++++
gcc/fortran/expr.c | 25 +++++++++++++++++++++++++
gcc/fortran/gfortran.h | 1 +
gcc/testsuite/gfortran.dg/pr103505.f90 | 9 +++++++++
4 files changed, 39 insertions(+)
create mode 100644 gcc/testsuite/gfortran.dg/pr103505.f90
diff --git a/gcc/fortran/array.c b/gcc/fortran/array.c
index fbc66097c80..5762c8d92d4 100644
--- a/gcc/fortran/array.c
+++ b/gcc/fortran/array.c
@@ -492,6 +492,8 @@ match_array_element_spec (gfc_array_spec *as)
if (!gfc_expr_check_typed (*upper, gfc_current_ns, false))
return AS_UNKNOWN;
+ gfc_try_simplify_expr (*upper, 0);
+
if (((*upper)->expr_type == EXPR_CONSTANT
&& (*upper)->ts.type != BT_INTEGER) ||
((*upper)->expr_type == EXPR_FUNCTION
@@ -524,6 +526,8 @@ match_array_element_spec (gfc_array_spec *as)
if (!gfc_expr_check_typed (*upper, gfc_current_ns, false))
return AS_UNKNOWN;
+ gfc_try_simplify_expr (*upper, 0);
+
if (((*upper)->expr_type == EXPR_CONSTANT
&& (*upper)->ts.type != BT_INTEGER) ||
((*upper)->expr_type == EXPR_FUNCTION
diff --git a/gcc/fortran/expr.c b/gcc/fortran/expr.c
index 4084d18f136..87089321a3b 100644
--- a/gcc/fortran/expr.c
+++ b/gcc/fortran/expr.c
@@ -2331,6 +2331,31 @@ gfc_simplify_expr (gfc_expr *p, int type)
}
+/* Try simplification of an expression via gfc_simplify_expr.
+ When an error occurs (arithmetic or otherwise), roll back. */
+
+bool
+gfc_try_simplify_expr (gfc_expr *e, int type)
+{
+ gfc_expr *n;
+ bool t, saved_div0;
+
+ if (e == NULL || e->expr_type == EXPR_CONSTANT)
+ return true;
+
+ saved_div0 = gfc_seen_div0;
+ gfc_seen_div0 = false;
+ n = gfc_copy_expr (e);
+ t = gfc_simplify_expr (n, type) && !gfc_seen_div0;
+ if (t)
+ gfc_replace_expr (e, n);
+ else
+ gfc_free_expr (n);
+ gfc_seen_div0 = saved_div0;
+ return t;
+}
+
+
/* Returns the type of an expression with the exception that iterator
variables are automatically integers no matter what else they may
be declared as. */
diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
index 1846ee4fd3c..24ad3ed4d06 100644
--- a/gcc/fortran/gfortran.h
+++ b/gcc/fortran/gfortran.h
@@ -3585,6 +3585,7 @@ void gfc_free_ref_list (gfc_ref *);
void gfc_type_convert_binary (gfc_expr *, int);
bool gfc_is_constant_expr (gfc_expr *);
bool gfc_simplify_expr (gfc_expr *, int);
+bool gfc_try_simplify_expr (gfc_expr *, int);
int gfc_has_vector_index (gfc_expr *);
gfc_expr *gfc_get_expr (void);
diff --git a/gcc/testsuite/gfortran.dg/pr103505.f90 b/gcc/testsuite/gfortran.dg/pr103505.f90
new file mode 100644
index 00000000000..522e53efcb2
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr103505.f90
@@ -0,0 +1,9 @@
+! { dg-do compile }
+! PR fortran/103505 - this used to ICE in compare_bound_mpz_t
+! Testcase by G.Steinmetz
+
+program p
+ integer, parameter :: a((2.)) = [4,8] ! { dg-error "scalar INTEGER" }
+ integer, parameter :: z(1:(2.)) = [4,8] ! { dg-error "scalar INTEGER" }
+ print *, a(1:1) ! { dg-error "Syntax error" }
+end
--
2.26.2
