Index: gcc/fortran/expr.c
===================================================================
--- gcc/fortran/expr.c	(révision 116013)
+++ gcc/fortran/expr.c	(copie de travail)
@@ -1014,6 +1014,7 @@
   int rank;
   int d;
   long unsigned one = 1;
+  mpz_t start[GFC_MAX_DIMENSIONS];
   mpz_t end[GFC_MAX_DIMENSIONS];
   mpz_t stride[GFC_MAX_DIMENSIONS];
   mpz_t delta[GFC_MAX_DIMENSIONS];
@@ -1052,6 +1053,7 @@
   for (d = 0; d < rank; d++)
     {
       mpz_init (delta[d]);
+      mpz_init (start[d]);
       mpz_init (end[d]);
       mpz_init (ctr[d]);
       mpz_init (stride[d]);
@@ -1085,15 +1087,16 @@
 	mpz_set_ui (stride[d], one);
 
       /* Obtain the start value for the index.  */
-      if (begin->value.integer)
-	  mpz_set (ctr[d], begin->value.integer);
+      if (begin)
+	  mpz_set (start[d], begin->value.integer);
       else
 	{
 	  if (mpz_cmp_si (stride[d], 0) < 0)
-	    mpz_set (ctr[d], upper->value.integer);
+	    mpz_set (start[d], upper->value.integer);
 	  else
-	    mpz_set (ctr[d], lower->value.integer);
+	    mpz_set (start[d], lower->value.integer);
 	}
+      mpz_set (ctr[d], start[d]);
 
       /* Obtain the end value for the index.  */
       if (finish)
@@ -1171,7 +1174,7 @@
 	  if (mpz_cmp_ui (stride[d], 0) > 0 ?
 		mpz_cmp (ctr[d], tmp_mpz) > 0 :
 		mpz_cmp (ctr[d], tmp_mpz) < 0)
-	    mpz_set (ctr[d], ref->u.ar.start[d]->value.integer);
+	    mpz_set (ctr[d], start[d]);
 	  else
 	    mpz_set_ui (stop, 0);
 	}
@@ -1205,6 +1208,7 @@
   for (d = 0; d < rank; d++)
     {
       mpz_clear (delta[d]);
+      mpz_clear (start[d]);
       mpz_clear (end[d]);
       mpz_clear (ctr[d]);
       mpz_clear (stride[d]);
Index: gcc/testsuite/gfortran.dg/array_initializer_2.f90
===================================================================
--- gcc/testsuite/gfortran.dg/array_initializer_2.f90	(révision 0)
+++ gcc/testsuite/gfortran.dg/array_initializer_2.f90	(révision 0)
@@ -0,0 +1,17 @@
+! { dg-do run }
+! Tests the fix for PR28496 in which initializer array constructors with
+! a missing initial array index would cause an ICE.
+!
+! Contributed by Paul Thomas  <pault@gcc.gnu.org>
+! Based on original test case from Samir Nordin  <snordin_ng@yahoo.fr> 
+!
+  integer, dimension(3), parameter :: a=(/1,2,3/)
+  integer, dimension(3), parameter :: b=(/a(:)/)
+  integer, dimension(3,3), parameter :: c=reshape ((/(i, i = 1,9)/),(/3,3/))
+  integer, dimension(2,3), parameter :: d=reshape ((/c(:2:-1,:)/),(/2,3/))
+  integer, dimension(3,3), parameter :: e=reshape ((/a(:),a(:)+3,a(:)+6/),(/3,3/))
+  integer, dimension(2,3), parameter :: f=reshape ((/c(2:1:-1,:)/),(/2,3/))
+  if (any (b .ne. (/1,2,3/))) call abort ()
+  if (any (reshape(d,(/6/)) .ne. (/3, 2, 6, 5, 9, 8/))) call abort () 
+  if (any (reshape(f,(/6/)) .ne. (/2, 1, 5, 4, 8, 7/))) call abort () 
+end