[PATCH] PR fortran/43996 -- Too large array constructor in SPREAD

[Steve Kargl <sgk@troutmask.apl.washington.edu>]

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The attached patch fixes an issue with SPREAD and the PARAMETER
attribute when an array constructor is too large for expansion.
gfortran now issues an error message and points to the 
-fmax-array-constructor.

Patch built on i386-*-freebsd and x86_64-*-freebsd.  There are
no regressions.  OK to commit?

2015-11-17  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/43996
	* simplify.c (gfc_simplify_spread): Issue error for too large array 
	constructor in a PARAMETER statement.

2015-11-17  Steven G. Kargl  <kargl@gcc.gnu.org>

	PR fortran/43996
	* gfortran.dg/pr43996.f90

-- 
Steve

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Index: gcc/fortran/simplify.c
===================================================================
--- gcc/fortran/simplify.c	(revision 230463)
+++ gcc/fortran/simplify.c	(working copy)
@@ -5991,8 +5991,8 @@ gfc_simplify_spacing (gfc_expr *x)
 gfc_expr *
 gfc_simplify_spread (gfc_expr *source, gfc_expr *dim_expr, gfc_expr *ncopies_expr)
 {
-  gfc_expr *result = 0L;
-  int i, j, dim, ncopies;
+  gfc_expr *result = NULL;
+  int nelem, i, j, dim, ncopies;
   mpz_t size;
 
   if ((!gfc_is_constant_expr (source)
@@ -6019,8 +6019,20 @@ gfc_simplify_spread (gfc_expr *source, g
   else
     mpz_init_set_ui (size, 1);
 
-  if (mpz_get_si (size)*ncopies > flag_max_array_constructor)
-    return NULL;
+  nelem = mpz_get_si (size) * ncopies;
+  if (nelem > flag_max_array_constructor)
+    {
+      if (gfc_current_ns->sym_root->n.sym->attr.flavor == FL_PARAMETER)
+	{
+	  gfc_error ("The number of elements (%d) in the array constructor "
+		     "at %L requires an increase of the allowed %d upper "
+		     "limit.  See %<-fmax-array-constructor%> option.",
+		     nelem, &source->where, flag_max_array_constructor);
+	  return &gfc_bad_expr;
+	}
+      else
+	return NULL;
+    }
 
   if (source->expr_type == EXPR_CONSTANT)
     {
Index: gcc/testsuite/gfortran.dg/pr43996.f90
===================================================================
--- gcc/testsuite/gfortran.dg/pr43996.f90	(nonexistent)
+++ gcc/testsuite/gfortran.dg/pr43996.f90	(working copy)
@@ -0,0 +1,7 @@
+! { dg-do compile }
+! PR fortran/43996
+!
+real, parameter :: a(720,360) = spread((/(j, j=1,720) /), dim=2, ncopies=360) ! { dg-error "number of elements" }
+real x
+x = a(720,360)
+end